Toxic Ancient

The deadliest of the Infested units, Toxic Ancients are constantly surrounded by a poisonous cloud that lingers for a short while even after one is slain. Just being close to them will induce poison damage (which bypasses a player's shields), making melee combat a very poor tactic against these Ancients; interestingly, their arm attacks do not poison players.

Toxic Ancients can be identified by the bright green glow from their heads, as well as their black and green bodies.

The toxic properties may be the result of a kind of decomposition, purposeful or accidental due to the plague. It is also noted that Toxic Ancients may be slightly faster than other Ancients, and will deliberately charge the player until it decides to hit you or run directly into you. They seem to attempt to get closer to you more than the other Ancients.

If a Tenno enters stealth while an Ancient is charging into attack range and remains in the same position, the Ancient's first attack will still connect but it will not continue to attack until its target becomes visible again. This may actually be counterproductive for the Toxic Ancient as the attack will often knock the invisible Tenno out of poison range.

Trivia

 * When in a subtle state (not in alert), Toxic Ancients do not emit toxic fumes out of their bodies.
 * The Toxic Ancients are the only Ancients that have their ability, then the word ancient.