The racoon barely fit in there, but somehow it got in. When I found it, it was sleeping peacefully curled up like a cat (they are nocturnal), but it woke up when it heard me. I released it right away, and it slowly made its way up a tree where it could resume sleeping for the day without being in the sun.
Racoons unfortunately can become pests, but they are otherwise pretty cute animals that are happy to eat from your hand, and do so gently (not like squirrels that can easily bite you and give you rabbies). We're not going to feed ours though since like bears you want them to remain wild, or they'll start going through your trash and become a pest.
At least they don't try to jump to our bird feeder like the squirrels, so that's good enough for me :)