There's a dude in a Poseidon costume protecting the Chase Field pool

You may recall that a few Dodgers players celebrated their NL West title with a dip in Chase Field's outfield pool last September, and that the D-backs were none too pleased about it.

Well, a group of determined Arizona fans seem to be taking it upon themselves to protect the hallowed waters this season. Poseidon, Ruler of the Sea (A.K.A. Logan Purser of Phoenix) leads the vigilante security force that also includes several blue-haired mermen, SeaWorld trainer/sea witch Ursula and someone who is either a) starring in a revival of "The Nightman Cometh" or b) the Yellow King. 

"We're here to protect the pool and make sure we get no interlopers and that anybody who's here is a D-backs fan all the way through," Purser said.

Just in case the pool isn't safe enough, here's D-backs mascot Baxter in a Speedo, for some extra muscle.

Photos and video via Amber Harding/MLB.com Real-Time Correspondent