Thumpers

First sighting of a Thumper on Highway 17.

Thumpers are large devices manufactured by the Combine, for the sole purpose of deterring Antlions. First seen in the level Highway 17 and more commonly in Sandtraps, the Thumpers seem to create a vibrational pulse by hammering the ground with a long piece of metal. This creates an effective perimeter for the Antlions which they cannot cross, due to being sensitive to the vibrations in the ground.

These devices can be used as a safeguard for the player earlier during the coastal levels, but are a hindrance to the player after gaining control of the Antlions using Bugbait. They can be activated or deactivated via an on/off button on their side, save some which have a remote generator to power them.

On the assault on Nova Prospekt's outer defences, the player must switch off numerous Thumpers located around the perimeter to allow the use of the Antlions that would now be under the player's control with the new weapon Alien Pheremones or 'Bugbait'.