Born of the 1997 revamp of Alpha Flight, Adrian Corbo and his half-brother Radius are mostly forgotten these days. With the power to transform his limbs into giant metal blades, he combines the mutant powers of Colossus and Wolverine into one, with the added benefit of being kinda dull. Adrian was quickly sidelined and was one of many incidental mutants to lose their abilities on M-Day, with little chance of revival.
The ‘Flex’ moniker was a childhood nickname, justified in that he supposedly flexed his muscles to transform. Given the number of blade-themed folks in play at 1990s Marvel, it could have been much worse.)