First appeared in: Resident Evil 2 (1998)
Otherwise known as Tyrant T-103, Trenchcoat or 'Trenchy', this hulking, bald, coat-wearing behemoth literally crashed into Resident Evil 2, thundering through a wall and proceeding to stalk the protagonists like a brain-hungry Terminator. Relentlessly pursuing our heroes, he was designed by Capcom to offer a different kind of opponent from the usual hordes of shuffling dead-heads. Throughout Resi 2, as you waded through rooms full of lickers, zombie dogs and other assorted mutants, it was the constant threat of X's reappearance that left players perpetually on edge.
In addition to being built like a multi-storey car park, X's main weapon was his unpredictability. Just solved a difficult puzzle? Revisiting a cleared corridor? Running for your life? There was no telling when the walking wall of flesh would turn up to rip your arms off and beat you round the head with them. It was an effective mechanic and one Capcom tried to revisit in Resident Evil: Nemesis. Unfortunately, Nemesis never quite captured the silent dread of Mr. X and will forever remain a lesser foe in the Resident Evil Canon