I have some scripts for you guys to show. And the error I'm getting.

BallHandler Script: (LocalScript)

local Tool = script.Parent.Parent
local StringVal = script.Parent

Tool.Equipped:connect(function(mouse) --whenever the player equips the tool, the Player's Name will be the Value inside this StringValue.
	local player = game.Players.LocalPlayer
    StringVal.Value = player.Name
end)

OnPlayerAdded IntValue Script: (ServerSide)

game.Players.PlayerAdded:connect(function(plr)
	local ankles=Instance.new("IntValue",plr)
	ankles.Name = "Ankles"
	ankles.Value = 60 -- How many times do they have to get crossed for them to fall	
end)

When "Ankles" Value Reaches 0: (LocalScript)

plr=game.Players.LocalPlayer
char=plr.CharacterAdded:wait()
while wait() do
	if plr.Ankles.Value <= 0 then
		wait()
		char.Humanoid.Sit=true -- Fall to the ground
		workspace.Sounds.Ankles:Play()
		char.Humanoid.PlatformStand=true -- Fall to the ground
		wait(2) -- How long until they get back up
		workspace.Sounds.Ankles:Stop()
		char.Humanoid.PlatformStand=false -- Fall to the ground
		char.Humanoid.Sit=false -- Stand back up
		plr.Ankles.Value = 50 -- How many times do they have to get crossed for them to fall
		wait()
	end
end

Decrease Player's "Ankles": (LocalScript)

for i,v in pairs(workspace:GetChildren()) do
	if v:findFirstChild("Humanoid") and v.Name~=script.Parent.BallHandler.Value and (v.Torso.Position-Tool.Handle.Position).magnitude<20 then
		local def=game.Players:FindFirstChild(v.Name)
		def.Ankles.Value=def.Ankles.Value-2
	end
end

--[[ This script is inside the Controls whenever a specific key is pressed. ]]--

Errors:

Screenshot of Error

Screenshot of Line Error

--The last screenshot uses deprecated keyboard input, but it still won't work if I use User Input Service.

I want it so that whenever a player presses a key, only the player's opponents will lose values, instead of their own teammates.

Thanks for all the help guys!

-LukeGabrieI aka EnergyBrickz