In Fallen London, I have acquired a Bat With Attitude; it was the result of a rare success on the Parliament of Bats opportunity card. It's a pet with exactly zero bonuses, and the description says
Fidgeting and unco-operative, but charmingly leathery, and it has its uses. Don't ask.
I've had this bat for quite some time (I've even become a Person of Some Importance in the meantime), and have yet to see it be even mentioned in storylets. I shall tempt fate, and ask: aside from its high sell price (12.5 Echoes), does it have any other uses?