Egg: This mottled green and brown egg looks like it's covered with bark
Hatchling: Born looking like a pile of leaves, Arborotherus hatchlings are difficult to see. Being very clumsy at birth they don't move around much, regardless if they are on land or floating in the water. Their coordination improves as they grow, but you will never see a graceful Arborotherus. They can however move very quietly when they want to, and this silence may be magical in origin.
Adult: Arborotherus grow to be the size of a large pony with short, thick legs and wide, padded feet. Their green and brown mottled skin has the texture of treebark and with their magical silence they can move through the forest without ever being seen or heard. Adult Arborotherus are herbivores, but can eat anything from grass to treebark and have been known to steal bread and pastries from their magi. Adult males have both tusks and horns to protect themselves; females have horns but no tusks.
General: Most Brontotherium and Onrosus would never meet, but occasionally they encounter each other where a marsh borders the plains. No one knows why it happens, but some pairs find themselves attracted and the resulting hybrids are both similar and different to their parent species. Arborotherus prefer to stay near rivers that run through forested areas, but also enjoy basking in the sun.