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Stage 4: KillBrick Path

Course progressStage 4 of 10
~45 min
Before you start

Finish Stage 3: Plank Walkway first. You have a yellow Stage 4 checkpoint at the end of the planks, and you've written a while … wait loop that flips properties.

Build

a wide path with three KillBrick hazards and the fifth checkpoint

Learn

how a `Touched` handler decides whether the toucher is a player, and how to set Humanoid.Health to 0

Ship

the KillBrick script — the exact pattern every later hazard reuses

The big idea​

This is the core hazard stage.

Every later hazard is a variation of the script you write here: listen for a touch, check if the toucher is a player, then set Humanoid.Health to 0.

The design lesson is that a wide path with hazards is harder than a narrow path with hazards.

A narrow path gives only one route, so the player feels punished. A wide path asks the player to choose.

Color also matters. Red says "danger" before the player reads a word. Visible danger is fair danger.

New words
Humanoid
the part of every Roblox character that handles health, walking, and jumping
:FindFirstChildOfClass
looks through a part's children for the first one of a given type; returns nil if none found
Health
a property on Humanoid; setting it to 0 triggers the death/respawn sequence
nil
Lua's word for 'nothing here'; you check `if x then` to know x is not nil
callback
a function you hand to an event so it runs whenever the event fires

Build it​

Step 1 — Build the wide path​

A flat wide path with enough room for the player to choose a route. Wider is harder.

A wide KillBrick path

Build this part

HazardPath

Block
Open recipe
Size
10 × 1 × 30
Color
Dark stone grey
Material
Concrete
Anchored
✓ Yes
Place
Starting at the Stage 4 yellow pad, stretching forward 30 studs

10 studs wide is enough for the player to walk around 1-2 hazards. Don't make it narrower — that breaks the design.

Step 2 — Build three KillBrick hazards from scratch​

Three identical cube hazards. Red, glowing, obviously dangerous. We'll script the first one and then duplicate it.

Build this part

KillBrick_1

Block
Open recipe
Size
4 × 4 × 4
Color
Really red
Material
Neon
Anchored
✓ Yes
Place
On the path, blocking the middle of one of the three lanes

Neon material makes the brick glow — adds to the danger signal. Anchored so it doesn't fall.

Now duplicate it for the other two hazards. Click KillBrick_1 in Explorer, press Ctrl+D twice. You get KillBrick_2 and KillBrick_3 identical to the first. Drag each to a different position on the path so the player has to weave between them.

Step 3 — Add the fifth checkpoint​

Build this part

SpawnLocation (Stage 5 — past the hazards)

Block
Open recipe
Size
6 × 1 × 6
Color
Bright violet
Material
Plastic
Anchored
✓ Yes
Place
At the far end of HazardPath

Also: check AllowTeamChangeOnTouch. Uncheck Neutral. Set TeamColor to Bright violet. In Teams, insert a Team named 'Stage 5', uncheck AutoAssignable, set its TeamColor to Bright violet.

Step 4 — Write the KillBrick script​

Now the central script of the course. In Explorer, right-click KillBrick_1 → Insert Object → Script. Open the editor.

Pass 1 — Listen for any touch

Delete the placeholder. Type this:

local brick = script.Parent

brick.Touched:Connect(function(otherPart)
  print("Something touched:", otherPart.Name)
end)

Press Play. Walk onto KillBrick_1.

Output prints lines like "Something touched: LeftFoot". Same as Stage 2, but now we will act on the touch.

Pass 2 — Find the Humanoid

Body parts like LeftFoot live inside the character model.

The character also contains a Humanoid. Extend the script so it finds that Humanoid.

local brick = script.Parent

brick.Touched:Connect(function(otherPart)
  local character = otherPart.Parent
  local humanoid = character:FindFirstChildOfClass("Humanoid")

  if humanoid then
    print("Found a player! Humanoid health:", humanoid.Health)
  end
end)

Press Play. Walk onto the brick.

Output shows "Found a player! Humanoid health: 100". That proves the script found your character, not just a random part.

Pass 3 — Set health to zero

Swap the print for the action:

local brick = script.Parent

brick.Touched:Connect(function(otherPart)
  local character = otherPart.Parent
  local humanoid = character:FindFirstChildOfClass("Humanoid")

  if humanoid then
    humanoid.Health = 0
  end
end)

Press Play. Walk onto KillBrick_1. You die immediately and respawn at the Stage 4 yellow checkpoint. You just built a KillBrick from scratch.

Step 5 — Copy the script to the other bricks​

KillBrick_2 and KillBrick_3 are duplicates of KillBrick_1, but the Script inside KillBrick_1 wasn't duplicated with them — the Script was added after the Ctrl+D. Two options:

  1. Easy way: In Explorer, click and drag the Script from KillBrick_1 down onto KillBrick_2 and KillBrick_3. Roblox copies it.
  2. Manual way: Right-click KillBrick_2 → Insert Object → Script, then copy-paste the code from KillBrick_1. Same for KillBrick_3.

Press Play. All three bricks kill on touch. Try to weave between them — the wide path makes it possible.

Understand it​

The script.Parent is KillBrick_1 itself. From there, the script listens for Touched.

The otherPart.Parent line is the trick.

When a player touches the brick, otherPart is usually a body part. The body part's parent is the character model, and the Humanoid lives there.

:FindFirstChildOfClass("Humanoid") safely asks, "is there a Humanoid here?" If not, it returns nil, and the kill logic is skipped.

Setting humanoid.Health = 0 tells Roblox the character died. Roblox handles the death animation, respawn timer, and checkpoint respawn.

Script anatomy

How this script turns a touch into a respawn

This is the first script where the event causes a real game consequence. It uses the same Touched pattern from Stage 2, then checks whether the toucher belongs to a player character.

local brick = script.Parent

brick.Touched:Connect(function(otherPart)
  local character = otherPart.Parent
  local humanoid = character:FindFirstChildOfClass("Humanoid")

  if humanoid then
    humanoid.Health = 0
  end
end)
  1. Line 1The script finds its own brick.

    Because the Script is inside KillBrick_1, `script.Parent` gives the code a reference to KillBrick_1. That is the part whose touch event we care about.

  2. Line 3Roblox waits for a collision.

    `brick.Touched:Connect(...)` tells Roblox: whenever anything touches this brick, run the function. `otherPart` will be the exact part that touched it, such as LeftFoot, HumanoidRootPart, or a loose prop.

  3. Line 4Move from body part to character.

    When a player touches the brick, `otherPart` is usually one body part. That part's Parent is the whole character model. The Humanoid is stored in that model, not inside the foot.

  4. Line 5Ask: is this actually a player character?

    `FindFirstChildOfClass("Humanoid")` returns a Humanoid if the character has one. If a normal Part touches the brick, there is no Humanoid, so this variable becomes nil instead of crashing the script.

  5. Lines 7–9Only players get the death action.

    `if humanoid then` means 'only run this if we found a Humanoid.' Setting `Health = 0` lets Roblox handle the death animation and respawn at the checkpoint team the player already earned.

Try this​

Learning beat

Try this

Three short experiments. Predict before you run, then test your guess.

Predict first

Remove the if humanoid then check entirely (delete lines 7 and 9, dedent line 8). Press Play. Walk onto the brick — it still works. Now drop a non-anchored Part onto the brick (insert a Part, uncheck Anchored, position it above). What happens? Predict before you test.

Compare

Change one KillBrick's BrickColor from Really red to Medium stone grey. Same Material, same shape, same script — only the color changed. Play through. Which brick do you instinctively avoid? Why?

Connect

The script's three core moves — listen for Touched, find the Humanoid, change a property — will appear in Stage 5 (Fireball), Stage 6 (Hidden Hazard), Stage 9 (KillWall), and Stage 10 (Puzzle button). What might change between them, and what will stay the same?

Test your stage​

  • Walk onto KillBrick_1, KillBrick_2, KillBrick_3 individually. Each kills and respawns you on the yellow pad.
  • Find a safe route between the bricks and walk it without touching any. Touch the violet pad.
  • Reset character. You respawn on violet.
  • Open the Output window during Play. There are no red error messages.
  • Design check. Stand at the yellow pad. Can a brand-new player see a safe route through the hazards in under three seconds? If not, move one brick to widen the safe corridor.

If it breaks​

  • The brick doesn't kill me. The Script is probably outside the brick. In Explorer, the Script should appear indented underneath KillBrick_1, not as a sibling at the Workspace level. Drag it inside the brick.
  • The Output shows attempt to index nil with 'FindFirstChildOfClass'. The otherPart.Parent was nil — meaning otherPart had no parent. Rare, but happens when parts are mid-deletion. Wrap the parent lookup: local character = otherPart.Parent; if not character then return end.
  • The Output shows attempt to perform arithmetic on a nil value or similar errors. You probably misspelled Humanoid (case matters — it's not humanoid with a lowercase h in the FindFirstChildOfClass argument). Re-type the "Humanoid" string carefully.
  • I die but I respawn at the wrong checkpoint. Your team setup from Stages 1–3 has a color mismatch. Open each Stage's Team in Explorer and verify TeamColor matches its SpawnLocation's BrickColor exactly.
  • The brick kills me even when I jump over it. The brick's hitbox is its size; if the brick is 4 studs tall, jumping requires clearing 4 studs of brick AND not landing on top. Reduce the brick height to 2 or 3 if you want jumping to be a valid strategy.
Coach notes

The Touched-handler script is the conceptual centerpiece of this course. Spend the full 45 minutes if a camper has any confusion — every later stage assumes this script is internalized. Specifically:

  • Walk every camper through Pass 1 (just print) and Pass 2 (find Humanoid + if humanoid then) before they try Pass 3. The temptation is to skip to Pass 3 and copy-paste. Don't let them.
  • Common confusion: campers think otherPart and character are the same thing. They aren't. Body parts are children of the character. Have campers add print("otherPart:", otherPart.Name) and print("character:", character.Name) to see the names side-by-side.
  • The if humanoid then check is the line campers skip the most. Symptom: their script "works" but throws red errors in Output every time a non-player part touches the brick. Teach them to check Output every Play.
  • Total time 45 min: 10 building, 20 writing+understanding the script, 15 testing variations.