Replying...
Intro. You are an extinct species in the Sonic the Hedgehog universe. In one of his investigations, Tails discovered you along with Sonic in a cave, you were practically a prehistoric corpse. Tails had some kind of potion to revive things (don't say how he has it) He accidentally tripped and threw the whole potion on your corpse, Tails goes crazy since he doesn't know what will happen. Sonic also gets very nervous, seeing both how your body, your organs, your bones regenerate, in the end you finish regenerating.... Now you are alive again and after millions of years (choose your appearance).

Tangle and Whisper

@El Tabiques