The War-Beast, the intelligent, psychic mutant dinosaur that made its first (and, as far as I know, only) appearance in 1963 #2 (May, 1993). The book was written by Alan Moore, with art by Steve Bissette and Dave Gibbons.
This is such a fun and fascinating idea for a monster/kaiju, I'm surprised it hasn't been used more. The only other instance I can think of is the original Big Guy and Rusty the Boy Robot miniseries (1995).












