And then there was that time that Red Hulk guest-starred on Battlestar Galactica:
It was such a big deal, it was even a 2-parter:
OK, OK, it wasn't Red Hulk (although, the idea of a monstrous Thunderbolt Ross taking on Commander Adama and crew is intriguing, in a fanfic sort of way).
But the beauty part? This wasn't even a Battlestar: Galactica story--at least not originally! Marvel's Tarzan book had been cancelled a few months earlier, and according to GCD, one of the scripts they had intended to use for Lord Greystoke "was reworked into a Battlestar Galactica story when Marvel's Tarzan title was cancelled."
So, really, it was a Tarzan/Battlestar: Galactica crossover. Who the hell needs fanfic??
Maybe Marvel has some leftover ROM scripts laying around that they could make into, oh, I don't know, a Stephen King comic book...
Marvel's Battlestar: Galactica #17 & #18 were from 1980, with covers by Bill Sienkiewicz and Michael Golden, respectively; written by Walt Simonson (plot) and Steven Grant (plot & script), drawn by Simonson & Klaus Janson (#17) & Sal Buscema and Janson (#18). Whew.