I just found a juvenile snake inside the top grill of my AC compressor two weeks ago.
I often get small toads and frogs underneath it, presumably for the cooling during hot summer months, and the snake was probably doing the same thing (or hunting the toads). He apparently got inside, then it kicked on, then he got chopped up, and almost made it out the top before expiring.
I just googled it, and this is apparently a common occurrence (all kinds of pics).
Here's a twofer.