In what's undoubtedly the natural technological step for those hollow mice we've seen folks like Ninja hawking for a few years, someone's gone and put a tiny fan inside a gaming mouse.
The Zephyr Pro promises a "more powerful and higher-performance sweatproof gaming mouse", in case you were unimpressed with the performance of your other sweatproof gaming mice.
The RGB-lit fan delivers a "stronger cooling blast directly into your palm", and I'll be honest: I question the efficacy of adding lights to a fan in a mouse, but it does, aesthetically, look really cool. I don't normally go in on chromatic gaming gear, but it actually looks pretty neat between the vents. At least the power draw should be negligible: a normal-sized case fan spinning at 3000 rpm might only draw 3W of system power.
Products for sweaty gaming hands aren't new to the market. Andy previously wrote about his experience with 'Gamer Goo', and found it to be surprisingly effective in improving his grip—though he did note that it was for him more relevant to controller use than mouse use.
In cases like this, it's important to remember that our own physical experience playing games might differ from someone else's. For players with palmar hyperhidrosis, or those with temperature regulation issues, a mouse with a built-in fan might make computer use more comfortable. Personally, as someone with painfully cold hands, I'm more of a candidate for a gaming space heater that sits over your keyboard, which was an actual Kickstarter project a few years back.
If you're interested in a cool, cooling mouse, you can pre-order the Zephyr Pro at Marsback for $69.