Hidden away on the Second Life Wiki, well not hidden very well, you’ll find the pathfinding cookbook. Described as a ready made solutions for some critters, it has some interesting concepts, it’s also incomplete or written with invisible ink.
In terms of interesting concepts we have such potential solutions as:
Sentient Treasure Chest
Treasure chest with legs. Sleeps, but runs and hides if anyone approaches.
Which makes me wonder if a wizard called Rincewind is having some input over at Linden Lab! There are sections for dogs, cats, rats, snakes, vultures which all sound like feasible critters people may want to engage with and then we get:
Wanders about hopping and approaches random people, lingers and moves on.