Zeke the witch could appear and vanish as if by magic behind a cover of smoke. Watch.
5 seconds sound clip from Scooby-Doo, Where Are You! - Which Witch Is Which (S1E13).
You can hear this line at 00:20:10.785 in the Blu-ray version of the episode.
Quote context
[...]
- Don't you recognize them, Sheriff?
- They were the ones that hijacked the armored car and sunk it in the swamp.
- Then they waited all this time till it was safe to look for it but couldn't find it.
- So they invented the witch and zombie act to keep people away.
- While they searched the swamp with a metal-tipped pole.
- I get it. The pole would make a metallic sound when it hit the armored car.
- Yeah, and then they'd pull it up with the winch.
- They had us fooled for a while with an old smoke screen trick. Show them, Velma.
- Zeke the witch could appear and vanish as if by magic behind a cover of smoke. Watch.
- Well, what started out as a fishing trip sure ended in a dandy mystery.
- Ah, come on, Scoob. Give up. You're not going to catch anything in that bucket of water.
- Hey! Finally! Lookie! Lookie! Lookie!
[...]