* Huge: Hippos are massive animals.
* Heavy: They are incredibly weighty.
* Hefty: Another word for their impressive size and weight.
* Horrific: Hippos can be dangerous and aggressive.
* Hairless: Hippos have very little fur.
* Herbivorous: They are plant-eating animals.
* Hydrophobic: Hippos don't like water, although they spend a lot of time in it. (This is a bit of a tongue-in-cheek adjective, as they're known for their love of water).
Let me know if you'd like more!