LensRentals recently got back a $10,000 Fujinon GFX100 medium format mirrorless camera from a customer who used it in dive housing and reported that it "suddenly died for no reason." After Fuji declared repair impossible and insurance claims were paid, LensRentals decided to take the camera apart and look inside.
It is always sad to read stories of how others lose or damage their camera gear, and I guess all of us would say, "That would never happen to me because I am cautious and won't risk my expensive equipment."
If you want to know what the market is like for high-end camera gear that has been destroyed by water damage, check out this eBay auction by a Hastings, Victoria-based Australian photographer who goes by the handle tallguy069. The poor guy accidentally dropped his Canon 1D Mark III DSLR and Canon 600mm f/4L lens ($10,000+ in gear) off a boat into saltwater, completely destroying the functionality of both pieces.
If you want to capture photographs or videos of otherworldly environments without using any computer generated imagery, one way is to create miniature worlds in your garage using a fish tank and salt water (a technique that has been used in numerous Hollywood movies). The video above is a tutorial on this trick by filmmaker and visual effects guru Joey Shanks.