Cool new pin. This is from a more recent episode. Treehouse XXIV (season 26) to be exact.
This is from the couch gag segment that was done by Guillermo del Toro. One of the best couch gags ever, period. Soo many references. Im sure theres a vid, you shoukd check it out if youve never seen it.
I think this is a reference to a Blade movie.. #treehouseofhorror