Thermal Discouragement Beam

The Thermal Discouragement Beam, or referred to in game as "Deadly laser", is a test chamber mechanic introduced in Portal 2.

The beam is fired in a straight line from an immovable device built into the wall or ceiling of a test chamber. The device will be coupled with a single receptacle (or multiple) placed in a different location. Directing the beam into the recepticle will activate certain mechanics that are crucial in reaching the chamber exit.

Thermal Discouragement Beams can be angled in certain directions with the use of the Discouragement Redirection Cube and portals. Additionally, the beam holds the ability to travel through transparent objects such as glass. It can also be used to destroy turrets that block the player's access. Touching the beam will only push the player away.