Crusher

Black Crushers are object that stomp to a wall that will kill Sonic with out losing rings.

Sonic the Hedgehog 2 (16-bit)
They first appear in Metropolis Zone where they move up and down sometime there at the top walls.

Sonic the Hedgehog 4 Episode 1
They appear in Mad Gear Zone where they do the same way they did in the second game.

Adventure of Sonic the Hedgehog
One crusher appear in the episode "Lovesick Sonic", it was use as a backup trap for Sonic but when he was knockout he dodge it. Scratch refers it as "The Smash Stapper".