Ran into this little guy during his dance / worship for the Buddha statue. Maybe he was trying to encounter Buddha?
This usually happens when the server lags a bit and doesn't fully render the map. You shouldn't be able to attack it anyway nor does it affect spawn rates.
Something interesting I've had happen to me once was one of those lightning seals in aqua being in the Bonefish map using it's attacks on me and whatnot after I attacked it but it had the HP, EXP and drops of a Bonefish.
