WalkSpeed is a property of the Humanoid object that determines the model's speed when being controlled by a player or when MoveTo() is activated. WalkSpeed is most often changed for running or sprinting mechanics, or lowered as a part of crouching mechanics.
The default WalkSpeed for ROBLOX characters is 16 studs/every 10 seconds. A higher number equals a higher speed, and a lower number equals a lower speed. Before an update, if WalkSpeed was negative, controls would be reversed. Now, you wouldn't be able to move at all. If WalkSpeed is high enough, a player can run through walls depending on how thick they are (i.e. having a speed of 250 might make you pass through a 1-stud-thick wall).
script.Parent.Touched:connect(function(part) -- make sure the part still exists if not part.Parent then return end -- make sure it's a humanoid local h = part.Parent:FindFirstChild("Humanoid") if not h then return end -- change to five times faster than default speed h.WalkSpeed = 16 * 5 end)