Grumpus will fly with his bed diagonally throughout the stage, passing freely over any blocks. Will fly in 5 seconds, after he stops, spinning his bed and move in last direction on Bomberman at where he's stopped. Grumpus has a weak spot vulnerable to targets: the rotary red panel in his bed. The player must always hit the red panel is towards the view of the bomb, either in horizontal or vertical, since the explosion range indeed. After 3 seconds stopped, Grumpus will jump and pound the ground and if he's pound the ground, will detonate any bombs. After 3 hits, Grumpus will spawn 4 snow men creatures which follows Bomberman at close-range. Snow men creatures takes 2 hits to destroy, but they all respawn afterwards.
Grumpus takes 6 hits to defeat. After defeated, Bomberman recovered the sixth and penultimate chip.
- In screenshots on Grumpus defeated, in the Japanese version, Grumpus appears asleep at a table with blanket down and down blanket, Bomberman asleep while reading the comics. In the American version, Bomberman is seen sleeping on Grumpus' lap.