Disneyland diver Thomas Self has discovered a lot of strange things in the waters of the Anaheim theme park, but he’ll never forget what he found one night in the Jungle Cruise river.

Self and his fellow divers were called out to investigate a mysterious banging sound after Jungle Cruise skippers repeatedly heard something thumping on the bottom of their boats in the temple ruins scene next to the Indiana Jones Adventure attraction.

The 55-year-old wet mechanic from Temescal Valley dropped into the ink black waters and was swimming beneath the Jungle Cruise boats when he suddenly came face to face with Mara, the ancient deity from the Temple of the Forbidden Eye who dooms all who dare look in her eyes.

“I wasn’t ready for it,” Self said during an interview at Disneyland. “I jumped back and banged my head on the bottom of the boat.”

Heavy rains had washed Mara’s head into the river from the shore of the Jungle Cruise attraction and boats were bumping against the submerged head. Self got the last laugh though, surfacing first with Mara’s stone head above his own.

“It scared the daylights out of everybody on the dock,” Self said.

Self is one of more than 70 Disney cast members featured in the new “One Day at Disney” docuseries on the Disney+ streaming service and the accompanying coffee table book.

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As a member of Disneyland’s scuba diving maintenance crew, Self inspects the boats, tracks and other submerged mechanics on the water attractions each night after the park closes. The unusual job on the overnight shift means Self spends most of his workday under water.

Disneyland’s crew of about a dozen full-time divers occasionally uses underwater lights, but they don’t help much, according to Self. That means much of their work takes place in the dark.

“You know where the stuff is,” Self said. “It’s just braille. You feel around. You know this is a sensor, this is a wheel, this is a chain. A lot of the work is reaching inside or through or under something. You can’t see it, so you just have to know what you’re doing, where your hands are and where your partner’s hands are. You learn by doing.”

The Disneyland divers work on all of the park’s water attractions — including the Jungle Cruise, Splash Mountain, It’s a Small World, Pirates of the Caribbean, Storybook Land, Mark Twain Riverboat, Sailing Ship Columbia and Finding Nemo Submarine Voyage.

“Nemo is the gem because it’s really clear water,” Self said. “It’s like a big, giant swimming pool. So we can see everything.”

SEE ALSO: Disneyland ride mashup: Jungle Cruise skippers take us on a comedic tour through the Haunted Mansion

The divers inspect everything from the boat propulsion systems on It’s a Small World to the underwater track switches in the Rivers of America to the audio-animatronic figures along the Jungle Cruise.

“A big part of it is a lot of the show elements and making sure that the hippos come up when they’re supposed to and the elephants do their thing,” Self said.

The divers work with Disneyland’s entertainment and decor teams on thematic installations and with the park’s engineering and operations teams to reduce maintenance times. Repairing the Jungle Cruise boats in the water and fixing the Small World launch system without draining the flume reduces dreaded down time and increases visitor satisfaction — top priorities for Disneyland’s top brass.

Divers wearing wetsuits with air tanks and goggles rotate in and out of the water on the biggest projects, which require plenty of pre-planning and teamwork.

“We count on each other,” Self said. “We know who’s where. We look out for each other.”

The seasoned veterans on the dive team train the next generation to follow in their wake.

“There’s not really a booklet for it,” Self said. “A lot of that is simply learned by getting in the water with the old timers as they’re doing it. Then we continue to pass it on.”

Occasionally a hide needs to be replaced on an animatronic hippo or a ride vehicle has to be pulled out of the water for extensive repairs. For the biggest jobs, helicopters are brought in to hoist animatronic elephants out of the Anaheim jungle.

The more mundane day to day issues involve wayward palm fronds and tree branches.

“Debris is the biggest issue,” Self said. “Occasionally the odd branch finds its way into the water and can get hung up in a track that could cause a problem.”

Man-made debris is also a problem — either blown in the water or dropped by visitors. The divers recover everything from smartphones and shoes to wallets and purses.

“Guests lose a lot of stuff.” Self said. “We’ve found some expensive wedding rings that the divers were able to recover.”

And then there are the turkey legs that visitors drop in the Rivers of America while cruising on the Mark Twain or Columbia. You might think nobody notices, but the Disneyland divers do. And they’d like you to stop.

It makes sense that Self has one of the wettest jobs at Disneyland.

“As a Navy brat, I never was far from the water growing up,” he said. “Water has always been a part of everything.”

Self started working at Disneyland as a cook at the Plaza Inn on Main Street U.S.A. during college before joining the U.S. Navy for a decade to work as an electromechanical technician on combat systems aboard the U.S.S. Abraham Lincoln all around the world. After the Navy, he returned to Disneyland as a machinist before adding “wet” to his title. Through the years, he’s helped launch Disney California Adventure, Hong Kong Disneyland, World of Color and Star Wars: Galaxy’s Edge.

SEE ALSO: Disney+ show recalls the chilling reception for Disney California Adventure: ‘I liked it better as a parking lot’

As a kid, “The Undersea World of Jacques Cousteau” was his favorite television show. He always wanted to be a diver. He just never imagined he would be a diver at Disneyland.

Self doesn’t relish his new celebrity as a Disney+ TV star or like being asked to autograph the glossy “One Day at Disney” coffee table book. He prefers to be underwater and out of the spotlight.

“I like the fact that most people don’t think about us,” Self said. “They come in and they just enjoy the park.”