- You may be looking for the Sonic Adventure enemy, E-06 Bladed Spinner (Spina).
Concept Artwork of Spina
It is a purple bat-shaped robot that attacks enemies by spinning bladed wings. It is similar to the E-06 Bladed Spinner robot from Sonic Adventure, except that it is purple instead of blue. It reappears in Sonic Advance 3.
It cannot be hit from the sides because of the shield of its wings, but a strike to the head can destroy it.