Mammals (like King Kong) discharge waste liquids and solids through separated discharge systems. Mammal large intestines absorb water back from the liquified intestinal contents with a resultant relatively compact, semi-solid turd.
Reptiles (like Godzilla) and birds, deliver both liquid and solid waste into a common collection sac organ called a cloaca. Thence, after mixing in the cloaca, the more soup-like mixture is discharged. They also tend to discharge smaller volumes in more frequent events.
Results 'on the ground' would favor a vote for King Kong.