"Christmas at Elvira's House of Mystery" from Elvira's House of Mystery Special #1 (DC, 1987) by Paul Gulacy
Twelve issue of recycled House of Mystery inventory, plus a Christmas special, hosted by the B-Movie queen, but it did give us linking material like this. Poor Cain. Ousted from his own House by a celeb. He knows how every writer who's been taken off a book in favor of JMS or Meltzer or Kevin Smith must feel.