Monster paintballs, the paintballs that are both loved and hated by players. A lot of players bring them to a BYOP (Bring Your Own Paint) paintball fields, and think its funny when players get hit by them. These are the most painful paintballs to get hit with on the market; it absolutely kills when you get hit by one. I think it takes the fun out of the game a little bit when you get hit by a rock hard paintball.