Reference or Ripoff: "Knuck Knuck! Who's Here?!" (Sonic Boom)

We're looking at another episode of Sonic Boom.

"Knuck Knuck! Who's Here?!"

Knuckles. WHY DOES THAT NAME HAUNT ME? It's the only thing I can remember...and that gruesome redesign. 

Knuckles gets amnesia and when he recovers he realizes he's that last of his kind. Saddened, he hunts for a new family.

Conclusion: Both. 

There are some obvious references, but the second part of the episode is stealing ideas from Adventures of Sonic the Hedgehog.

• To an outsider, the title looks like a knock-knock joke, but to meme-fans, it's clearly alluding to the infamous "Knock Knock it's Knuckles."  
• The characters poke fun at the idea of amnesia (specifically on TV sitcoms), possibly with the 90s Sonic cartoons in mind as each had an episode where a character lost their memory/identity ("Blank-Headed Eagle," "No Brainer," and "Who Do You Think You Are?").
• Or Shadow the Hedgehog, who lost his memory in Sonic Heroes. 
• However, considering how common that situation is on shows, they could simply be making fun of TV in general (and themselves). 
• The ending where Knuckles (well, Amy, technically) concluded that Sonic/Tails/Sticks/Amy was his family was reminiscent of when Manic realized that his true home was with his siblings in Sonic Underground (Mobodoon).     

Group hug!

"Tails' New Home"

Didn't see that one coming. Not at all. 

After Tails is hurt, Sonic sets off to find him a new family so he'll stay out of harm's way.

Just simply the idea of finding foster parents (and ending up with "parents" that where actually bad guys). Combine this with "The Sidekick," another similar episode, and AoStH was completely ripped off.