Anti-Teleport Kill.lua

local Players = game:GetService("Players");
local MaximumMovementDistance = 50; -- How many studs a Player can move in one server game tick.
local TeleportDistanceThreshold = 2; -- How many studs away from the estimated teleport position the player needs to be.
local InfractionsBeforeBan = 2; -- How many times a Player needs to be caught before a ban will occur. This helps prevent possible false bans.

local BannedPlayers = {};
local InfractionTable = {};
local LastPositionsTable = {};

Players.PlayerAdded:Connect(function(player)
	if (BannedPlayers[player.UserId] == true) then
		player:Kick();
		return;
	end

	player.CharacterAdded:Connect(function(character)
		local enabled = true;
		local rootPart = character:WaitForChild("HumanoidRootPart");
		LastPositionsTable[player] = rootPart.Position; -- Set this every time the character is added to avoid false flagging issues.
		
		character:WaitForChild("Humanoid").Died:Connect(function()
			enabled = false; -- Disable on death so flying body parts don't cause a false trigger.
		end);
		
		rootPart:GetPropertyChangedSignal("CFrame"):Connect(function()
			if (enabled) then
				local cframe = rootPart.CFrame;
				if (LastPositionsTable[player] == nil) then
					LastPositionsTable[player] = cframe.Position;
				end
				
				if ((LastPositionsTable[player] - cframe.Position).Magnitude >= MaximumMovementDistance) then
					warn(string.format("Player [%s] moved more than the threshold distance of %d in one server game tick! Checking for exploiters.", tostring(player), MaximumMovementDistance));
					for _, otherPlayer in ipairs(Players:GetPlayers()) do
						if (otherPlayer ~= player and otherPlayer.Character ~= nil) then
							local otherRootPart = otherPlayer.Character:WaitForChild("HumanoidRootPart");
							local exploitedCFrame = otherRootPart.CFrame + otherRootPart.CFrame.LookVector;
							
							if ((exploitedCFrame.Position - cframe.Position).Magnitude <= TeleportDistanceThreshold) then
								InfractionTable[otherPlayer] = InfractionTable[otherPlayer] and InfractionTable[otherPlayer] + 1 or 1;
								warn(string.format("It appears player [%s] is exploiting and attempting to kill others! Current infractions: %d", tostring(otherPlayer), InfractionTable[otherPlayer]));
								
								if (InfractionTable[otherPlayer] >= InfractionsBeforeBan) then
									warn(string.format("Player [%s] has reached the infraction ban threshold and is now banned!", otherPlayer));
									BannedPlayers[otherPlayer.UserId] = true;
									otherPlayer:Kick(); -- I don't suggest adding a message here so they don't know why they were banned immediately.
								end
							end
						end
					end
				end
				
				LastPositionsTable[player] = cframe.Position; -- Update the position of the player in the position table for next frame.
			end
		end);
	end);
end);

-- Clean up table entries to reduce memory usage.
Players.PlayerRemoving:Connect(function(player)
	LastPositionsTable[player] = nil;
	InfractionTable[player] = nil;
end);