SAN DIEGO -- Welcome to the Underwater Torpedo League.
"The sport works similar to -- if you can imagine -- water polo with the nets on the surface. If you shrink that down to minute hockey nets and put them down at the bottom of the pool in 25 meters, that's how we play," co-founder Prime Hall said.
If you've never seen this before, you're not alone.
The relatively new sport typically has teams of five playing against each other.
But in practice, they go two-on-two as the players try to put the 10-ounce torpedo in the goal.
The first team to score five goals -- playing the best two out of three matches -- wins.
Now in its third year, the sport attracts all kinds of athletes: NFL players, Olympians, average Joes and even Bellator MMA fighters like Liz Carmouche, who also coaches.
"I wanted to be able to give back and help people achieve the same confidence I had in the water because I knew where I came from of being like, 'I can't swim,'" Carmouche said. "No one believes me, but really -- if you had seen me a year ago, you would really understand how embarrassing it was for me in the pool."
UTL has seven teams from La Jolla to Hawaii and Las Vegas to Miami. Its season spans eight weeks, with the two best teams playing for the coveted "Aqua Cup."
Hall, a marine from 2005 to 2017, worked as a water survival instructor and ran a facility on Camp Pendleton training thousands of marines. He co-founded UTL and Deep End fitness after making a breakthrough on base.
"One of the things I have found to help training is using something like the torpedo to occupy someone's focus, which removes any anxiety or fears of being in the water, going underwater and doing whatever training they need to do," Hall said.
The underwater strength training helps players build patience and find the ability to face things they may not be totally comfortable with.
"One of my favorite memories is scoring the goal," Carmouche said. "To be able to get in there and swim was such a state of distress for me, just because I felt I was so bad at it and was the weak link. I'm the worst person on the team, and I hate being that person. And that was my, 'Hey I'm not too bad at this, and this is a lot of fun' (moment)."
Carmouche plays and trains with fellow Bellator MMA fighter Ilima-Lei Macfarlane, who said deep water fitness and UTL changed her fight.
"The mental game is so much better. Learning how to do stuff underwater when you're cut off from your life basically … Your air … Your life source," Macfarlane said. "It can definitely put you in some dark places, but learning how to control that ... It took my fight game to the next level, mental-wise."
Deep End Fitness and UTL are both open to non-swimmers and professional athletes alike. The cost of a drop-in pass starts at $25.