In Bomberman, Boma moves in a repetitive manner and only changes direction when colliding with a wall. It appears only in Round 3: River.
In Bomberman II, Boma moves at a speed of 3 and can choose to change direction. Occasionally after a while it stops and turns into a bomb that explodes at 9x range. Boma is indestructible whenever it is in form a of bomb. It appeared first in Area 4-8 and after, in rest of the levels.
In Bomberman '93, Boma appears in Area C: Planet Inferno. This time, Boma has a speed of 4 and may pass through soft blocks.