What did I do wrong?

This script isn't working. It was supposed to rotate a model but it did nothing. Can you help me? Here's the script:

while true do
wait(0.2)
game.Workspace.Mudkip:TranslateBy(Cframe.new(0, 0, 0.5))
end

You need to do it:

while true do
	wait(0.2)
	game.Workspace.Mudkip.CFrame = game.Workspace.Mudkip.CFrame * 		CFrame.fromEulerAnglesXYZ(Cframe.new(0, 0, 0.5)
end