"Several tribal curses were invented just to describe Infiltrators who sneak around enemy bases placing mines." In-game description.
When deployed Prism Mines emit a laser trip-wire which will detonate the mine when an enemy player crosses it. The enemy player will take the full 800 damage no matter how far they are from the mine when it detonates. The laser can be seen from a short distance away, but is invisible after a few feet. The mine itself is quite large and can be seen easily if not concealed. Once deployed an icon will appear in the bottom left of the player's HUD until the mine is destroyed.