The show might be a decade-plus past its prime, but no one can deny that “The Simpsons” couch gags in recent years have been some of the most memorable.  The couch gag by Banksy, which aired last October, was a controversial head-turner for sure. But last night’s contribution by John Kricfalusi — best known as the creator of “Ren and Stimpy” was not only brilliant, but a great surprise. Creepy and uniquely John K., the sequence seems to also pay tribute to the pink elephants sequence in Dumbo with its overtly psychedelic animation and background music reminiscent to the film.