According to Variety, the studio has optioned Larry Doyle's upcoming novel Go Mutants! It's a teen comedy / adventure story set in a world where all those classic 1950s alien invasion movies actually happened. A few decades later, the offspring of those invasions have assimilated among the rest of the population, and are happily attending high school.
It's too early to tell if it'll be another Monster Squad, as the book doesn't hit store shelves until next summer, but Doyle promises you'll see cameos from Gort and the Creature from the Black Lagoon. One of those is not like the other, so all bets are off as to who else you might see, but I'd put money on the Mole Man and the Metaluna Mutant. Perhaps he'll reach beyond the creature feature cast, and throw in the Invisible Man -- you can't tell me that sly creep didn't use his gift to father a few brats and avoid the child support.