While some still know him best for playing Bernard the elf in the first two Santa Clause movies and The Santa Clauses TV series, David Krumholtz has assembled many other notable roles over his career, including Charlie Epps in Numb3rs and Isidor Isaac Rabi in Oppenheimer.
In other words, Mole Man has yet to be properly adapted in live-action, so using him as the driving threat would be a good way for The Fantastic Four to stand out from the previous movies, whether David Krumholtz is playing him or not.
The Thing, in the MCU’s The Fantastic Four reboot didn’t work out.
The Fantastic Four is due in theaters on July 25, 2025, and both 2005’s Fantastic Four and its sequel Fantastic Four: Rise of the Silver Surfer can be viewed with a Disney+ subscription.