Minus

Minuses are a mid-tier enemy in the game, and moves either vertically or horizontally.

Behavior
A Minus can be a problem, generally they guard the exit, and help Piluses to trap you. They like to move right outside your reach, blocking you from moving.

Tactics
The only way to destroy it is if you move an odd number of moves to get there. The only way to move an odd number of moves there is to destroy something. So, destroy something then destroy the Minus.