The successor to foxes on a trampoline...

Pine martens on a swing! The playfulness is absolutely adorable.

I would love to see a pine marten. Alas, they are furtive beasts, the UK ones not even prone to eating ones brake cables as beech martens do. Or in one case, the Large Hadron Collider. It was subsequently stuffed and displayed in an exhibition on human-animal interactions in Rotterdam.