Crawl
From Sonic Retro
Crawl (called Gaadon in the Japanese Manual), found in Casino Night Zone, has a bumper included, so if you try to perform a spin attack from the front it'll bump you away! So, you have to jump over it and quickly attack from the back as the only method of destroying it.
Technical Information
3D23E Crawl sprite offset
901A4
Crawl sprite art (Nemesis Format, 42 blocks)
C8
Sprite function