The paradoxis frog begins its life as the Paradoxis Polliwog, a giant carnivorous tadpole with identical statistics and abilities as a Medium size crocodile (MM Animals — although a polliwog has gills, and does not need to hold its breath). After living three months as a giant tadpole, it transforms rapidly over a period of 3d4 days, shrinking into a paradoxis frog of Fine size. Although paradoxis frogs are carnivorous too, at their size they are of little threat to anything but insects and minnows.

At the end of summer a paradoxis frog dies and its body implodes as it is absorbed into the 1d4 eggs in its egg sac. These frog eggs are made of a stinging, jellyfishlike substance, which makes them unpalatable and typically undisturbed through the fall and winter months. Eggs grow until they reach the size of an adult crocodile; then the Paradoxis Polliwogs emerge and begin feeding their carnivorous appetites.