Endangered Species, Eli Roth's Giant monster/kaiju flick

Seems this has been on the burner for awhile but is now moving right along. Eli has stated his monster will be something grounded in realality, just freaking huge! No aliens,robots,or virus; just something unexpected that once roamed the earth now runing amuk. Well dinosaurs,big apes,giant snakes,mega sharks,giant octopuses, and bugs have been done over and over. So what exactly will Eli Roth mutate to giant size?