Knuckles the Echidna

Knuckles the Echidna (ナックルズ・ザ・エキドゥナ, Nakkurusu za Ekiduna) is major character in the Sonic series as well as the rival and friend of Sonic the Hedgehog, he is the guardian of the Master Emerald. He makes an appearance in Super Smash Flash and Super Smash Flash 2 as a playable character.

In Super Smash Flash
Knuckles is a starter character from the large Sonic series roster in SSF. He includes 5 different attacks:

Also, Knuckles can use his jump as an attack to deal damage.

In Super Smash Flash 2
Knuckles may or may not reappear in SSF2, after the entire roster was hidden from non-devs. Although it is unlikely that he won't return, his true fate is curently unknown