K.K. Plays Covers

[Bacon Boy]

When I was listening to some K.K. Slider songs a long time ago, I noticed this:

Spoiler

(Most commonly recognized one)

I know these aren't all of them; there are probably more. Post them if you would like. Anyone else ever recognized this?

 

[ACCF18]

lol..

 

[MDofDarkheart]

OMG!
I never noticed it before!
I wonder what other ones are covers of other game songs or real artist songs!