Teemo has no trail.
If i remember correctly when you put a point in your W Teemo gains a bright blue trail that indicates he has his movement speed but it isn't appearing anymore and when you activate the ability it appear then disappears.
If i remember correctly when you put a point in your W Teemo gains a bright blue trail that indicates he has his movement speed but it isn't appearing anymore and when you activate the ability it appear then disappears.