Ancient Disruptor

These reddish Ancients have a very special ability. A player who is struck by one's arm will be completely drained of all his/her energy and shields; the player's HUD will also temporarily suffer from noise and distortion, as if the Warframe's systems have been scrambled. Players will be unable to earn energy from energy orbs during the scramble effect.

Hint: If you use melee Block or Roll, they won't drain your energy and shields.