Hold Breath. The hippopotamus can hold its breath for 10 minutes.
Multiattack. The hippopotamus makes two Bite attacks.
Bite. Melee Attack Roll: +7, reach 5 ft. Hit:16 (2d10 + 5) Piercing damage.
Use these stat blocks to represent the creatures they're named for or other similar creatures. For example, the Panther stat block can also represent a mountain lion, while the Giant Goat stat block might represent a buffalo. Any of these stat blocks might also serve as fantastical animals with distinctive names and cosmetic details unique to your D&D adventures.