I used it to harrass a character in a maratime campaign. I basically paid children to bring me live, unharmed seagulls (gave them a net and money for frenchfries to get the job done) and then cast animal messenger via Ritual Casting over and over on the massive flock of birds. Location? The altar a mean, exploitative NPC was tending, which was a one hour walk from me. Message? A doom and gloom portent decrying the NPC as a false prophet/corrupt clergy (and he really was). Recpient? Some long, drawn out, highly specific descrption that was unlikely to show up in game. This forced the birds to stay in the area until the spell expires or the trigger shows... meaning a giant flock of seagulls is slowly gathering and pooping on everything in the NPC's temple. One trip there and a Disguise Self spell later, my character walks in appearing like the described recipient and the whole flock of seaguls starts screaming at once about the NPC and how he's a false prophet in front of all his followers during mass. It was the first step in our party's plan to drive the guy out of the city.
This is awesome.