Dog was originally a guard dog on our very first mission, but rather than fight past him, we were appalled at his living conditions, fed and watered him, and charged his owners yelling "This is no way to treat your pets!" Dog subsequently attached himself to my paladin, Rook, and has been our faithful NPC ever since. It helps that our GM plays him very well. Dog wanders between begging for bacon, bestowing kisses, and occasionally doing a Little-Timmy-Trapped-In-The-Well routine when neccessary to move the plot along.
Today we're on an airship, cleaning up the mess left by a battle with undead rats, and we discover some crates bearing the seal of our current enemy. By the end of the session (following another battle and much intrigue) we're trying to figure out if any of the crates need to be opened (which we don't want to do, for fear of alerting the crew of something suspicious going on.)
And so, displaying the disgusting ingenuity for which PCs are famed, we solved the problem.
Rook had been playing fetch with Dog, using one of the dead rats--(Okay, yes, unhygenic, I grant you, but Dog enjoyed it, and Rook has gauntlets on)--and our cleric Tarab suggests we try to use Dog to find out if any of the crates are suspicious. So after a few false starts, we get the bright idea to throw the dead rat at each questionable crate, and see if Dog is willing to fetch it, or if he starts acting weird.
Dead Rat Fetch Scrying. And it actually worked. We uncovered a weird spell on one, and another that Dog gave a wide berth to, which is highly suspicious.
Who needs intelligence rolls and knowledge skills when you've got a dog and a dead rat?
It reminds me of how my shaman used to test the environment on the other side of scary portals using a live mouse on a string....