Sonic Boom - Season 2 - Eps 12: Knuck Knuck! Who's Here?
During a fight against Eggman, Knuckles suffers amnesia. His friends try to help, reminding him of his worst blunders via flashbacks. But he becomes more depressed when he learns that he is the last of his kind - the final echidna. Feeling all alone in the world, Knuckles sets out to find a foster family among the Villagers who might be willing to take him in.
About Sonic Boom

Title: Sonic Boom
First Air Date: 2014-11-08
Last Air Date: 2017-11-11
Status: Ended
Rating: 7.426/10 (from 352 votes)
Language: EN
Seasons: 2
Total Episodes: 104
Network: Cartoon Network Boomerang
Genres: Action & Adventure, Animation, Comedy, Sci-Fi & Fantasy, Family
Production Companies: OuiDO! Productions, Technicolor Animation, SEGA of America
Synopsis
The speedy blue hedgehog Sonic with sidekick Tails and pals Knuckles, Amy and Sticks tries to ward off the evil plans of Dr. Eggman, who is hellbent on taking over the world. Sonic faces regular battles with Eggman's henchmen, including loyal robots Orbot and Cubot, evil interns, and giant, robotic monsters.
Cast

Roger Craig Smith
Sonic / Dave the Intern / Young Gogoba (voice)

Colleen O'Shaughnessey
Tails / Zooey / Mrs. Vandersnout / Belinda (voice)

Travis Willingham
Knuckles / Soar the Eagle / Obliterator Bot / Old Monkey / Mr. Slate (voice)

Cindy Robinson
Amy Rose / Perci / Elderly Gogoba / Justin Beaver (voice)

Nika Futterman
Sticks / Diane Aardvark (voice)

Mike Pollock
Dr. Eggman / Fastidious Beaver / Mayor (voice)

Kirk Thornton
Orbot / Shadow the Hedgehog (voice)

Wally Wingert
Cubot / Gogoba Chief / Dixon / D.B. Platypus (voice)

Bill Freiberger
Comedy Chimp / Lady Walrus (voice)