Nyan Chipmunk aka Negative Effect Nyan Cat was a spoof originally created by YouTuber "DrawMyDreams".
Not to be confused with "G-Major Nyan Cat", this nyan cat has negative colors and flies to the normal nyan cat theme, but with a twist; the music is pitched up to sound like a chipmunk from "Alvin and the Chipmunks".
YouTuber "Philip Goto" made another version where the music is a different pitch, but this version has the original Nyan Cat with Alvin's head pasted over the original nyan cat's face.
Like Slo-Mo Nyan Cat, this nyan is still the original song and video, but had an effect put on it; in this case, it has been pitched up.
The original version of Nyan Chipmunk had a negative colored nyan cat, which is unrelated to Alvin and the Chipmunks.