Lvl 9 wizard, worshipping mystara, magma mines. Crystal ball, not much else in equipment. Fireball, Blood to power, poison, IMAWALL.
Used IMAWALL on a green spawned snake, Fireball/poison/regen Durr? the shaman (phys immune) down to a few % health. Fireballed and levelled up. Game crashed completely - all characters monsters shops etc disappeared, UI bar on right went blank, a number of the map tiles were overlayed with black.
Was worshipping mystara, had several ranks of magic perk, mana leak, and several ranks of 'weakening'.