A cat.
The local Sheriff's Department range is in the middle of nowhere, and questionable individuals probably dump animals out there. Anyhow, I'm changing my target on the 100 yard range when I turn around and there's a fluffy grey cat standing behind me. Never saw where he came from. Friendly and healthy looking, I pet him a bit and start walking back to the tables, encouraging the cat to follow. So of course it lays down. Ended up carrying the big booger back (as was its plan all along, I'm sure) while it purred away. Brought it to the RSO's office while shooting resumed, cat didn't even flinch at the gunfire. RSO said it had been there for a few weeks and that they had kinda sorta unofficially adopted it for rodent control, giving it food and treats. RSO confirmed cat was either fearless or stupid, not sure which. I wasn't quite a regular at the range, and I never saw Officer Fuzzbutt again.