Create player hazards

Right now, players can fall off any platform with no consequence. This section walks you through creating a large invisible hazard at the same height as the water in your game. When a player falls into the hazard, their health is reduced to zero and they respawn at the start of the game.

Create a basic water hazard

Build with Assistant

In Workspace > World, create a new folder named Hazards.
Inside the Hazards folder, create a block Part named Hazard with Size 825, 1, 576 and CFrame.Position 174, -6.5, 38 so the part covers the water around the island and platforms.
Set Transparency to 1 so the part is invisible and the actual water appears to be the hazard, disable CanCollide so players fall through it into the water, and enable Anchored so physics doesn't move it.

Build it Yourself

In the Explorer, hover over the World model, click ⊕, and insert a new Folder. Rename it Hazards.
Inside the Hazards folder, insert a block part and rename it Hazard. Use the Move and Scale tools to flatten and stretch the part so it covers the water around the island and platforms. The sample uses Size = 825, 1, 576 and CFrame.Position = 174, -6.5, 38.
With the part still selected, in the Properties window:
1. Set Transparency to 1 so the part is invisible — the actual water below is what the player sees as the hazard.
2. Disable CanCollide so players fall through the part and into the water instead of standing on the part.
3. Enable Anchored so physics doesn't push the part around.

Detect when players touch the hazard

The hazard doesn't do anything until you write a script that listens Touched and lowers the player's health to zero.

Build with Assistant

In ServerScriptService, create a Script named HazardService with the following code:

```lua
local Players = game:GetService("Players")
local Workspace = game:GetService("Workspace")

local hazardsFolder = Workspace.World.Hazards
local hazards = hazardsFolder:GetChildren()

local function onHazardTouched(otherPart)
	local character = otherPart.Parent
	local player = Players:GetPlayerFromCharacter(character)
	if player then
		local humanoid = character:FindFirstChildWhichIsA("Humanoid")
		if humanoid then
			humanoid.Health = 0
		end
	end
end

for _, hazard in hazards do
	hazard.Touched:Connect(onHazardTouched)
end
```

Build it Yourself

In the Explorer, hover over ServerScriptService, click ⊕, and insert a new Script. Rename it HazardService. Put it in ServerScriptService to keep the code on the server, where players can't read or make changes to it.
Replace the default code with the following code to loop through every part in the Hazards folder and set the player's health to zero when they touch the hazard:

local Players = game:GetService("Players")
local Workspace = game:GetService("Workspace")

local hazardsFolder = Workspace.World.Hazards
local hazards = hazardsFolder:GetChildren()

local function onHazardTouched(otherPart)
	local character = otherPart.Parent
	local player = Players:GetPlayerFromCharacter(character)
	if player then
		local humanoid = character:FindFirstChildWhichIsA("Humanoid")
		if humanoid then
			humanoid.Health = 0
		end
	end
end

for _, hazard in hazards do
	hazard.Touched:Connect(onHazardTouched)
end

Code explanation

The HazardService has many similarities to CoinService. However, instead of collecting a coin, the player has their health set to 0 when they touch a hazard.

Feel free to modify, add, or remove hazard objects in your game to create unique obstacles. As long as they are contained in the Hazards folder, the code loop connects the event handler to all of your hazards.

Connect to the player lifecycle

The player lifecycle represents events that occur when players interact in your game, such as joining, leaving, or respawning. You need to connect handlers to these events to execute logic for each major lifecycle event.

Build with Assistant

In ServerScriptService, append the following code to the bottom of the existing CoinService Script (don't replace any of the existing code — add this after it):

```lua
local function onPlayerAdded(player)
	-- Reset player coins to 0
	updatePlayerCoins(player, function(_)
		return 0
	end)

	player.CharacterAdded:Connect(function(character)
		-- WaitForChild would stop the player loop, so below should be done in a separate thread
		task.spawn(function()
			-- When a player dies
			character:WaitForChild("Humanoid").Died:Connect(function()
				-- Reset player coins to 0
				updatePlayerCoins(player, function(_)
					return 0
				end)
			end)
		end)
	end)
end

-- Initialize any players added before connecting to PlayerAdded event
for _, player in Players:GetPlayers() do
	onPlayerAdded(player)
end

local function onPlayerRemoved(player)
	updatePlayerCoins(player, function(_)
		return nil
	end)
end

Players.PlayerAdded:Connect(onPlayerAdded)
Players.PlayerRemoving:Connect(onPlayerRemoved)
```

Build it Yourself

In the Explorer, open the CoinService script inside ServerScriptService.
Scroll to the bottom of the file (don't replace the existing coin-collection code) and add the following lifecycle handlers to reset a player's coin count when they join the game and when they die:

local function onPlayerAdded(player)
	-- Reset player coins to 0
	updatePlayerCoins(player, function(_)
		return 0
	end)

	player.CharacterAdded:Connect(function(character)
		-- WaitForChild would stop the player loop, so below should be done in a separate thread
		task.spawn(function()
			-- When a player dies
			character:WaitForChild("Humanoid").Died:Connect(function()
				-- Reset player coins to 0
				updatePlayerCoins(player, function(_)
					return 0
				end)
			end)
		end)
	end)
end

-- Initialize any players added before connecting to PlayerAdded event
for _, player in Players:GetPlayers() do
	onPlayerAdded(player)
end

local function onPlayerRemoved(player)
	updatePlayerCoins(player, function(_)
		return nil
	end)
end

Players.PlayerAdded:Connect(onPlayerAdded)
Players.PlayerRemoving:Connect(onPlayerRemoved)

Code explanation

The code defines functions to reset coin counts during the appropriate lifecycle events:

Players.PlayerAdded fires when a player joins the game, and sets the coin count to 0.
Player.CharacterAdded fires when a player's character model is added to the world. It occurs after PlayerAdded and whenever the player respawns.
Humanoid.Died fires when a player dies, and sets the coin count to 0. task.spawn() creates a separate thread for handling this, so other aspects of the player life cycle can execute.
Player.PlayerRemoved fires when a player leaves the game to clean up player state.
This code contains a potential issue where players could collect coins before the Players.PlayerAdded event executes and then have their coin counts reset to zero. To mitigate this issue, consider solutions such as code scheduling or freezing the player's character until initialization finishes. However, these solutions involve more complex scripting concepts that are beyond the scope of this tutorial.

Playtest

Select Test from the dropdown and click Play. Collect a few coins, then jump into the water. You character should die and respawn at the start, with their coin count reset to 0.