The ThunderLOLCats Nyan Cat is a Nyan Cat that was featured in a skit called ThunderLOLCats in the Cartoon Network TV show MAD. In the skit the Thunder Cats are attacked by tons of internet memes and then Lion-O must use even more "ridiculous" memes to defeat them. He then uses a Thunder Cats Nyan Cat and defeats the memes.
-bye me

A lot of people think it’s funny to have a bunch of memes just randomly attack someone. In this case, a Nyan.