Blocker moves slowly in a straight line until it collides with a block, bomb, or other enemy, at which point it pauses and then chooses a random direction and continues to move. It may choose to reverse directions even if it is not at a dead end. It will harm the player on collision.
When Blocker stops to turn, it may produce a Soft Block before moving on, provided that it is not trapped.
It's also in Bomberman Portable, notably in the Lava World.
- Super Bomberman 2 Hudson Official Guidebook, pg. 27, 41