Mimic (All You Need Is Kill)

The Mimics are artificial creatures who invaded Earth in an attempt to xenoform it for another race.

Biology
Mimics are heavy, silicon-based artificial lifeforms, enclosed in armor that requires a 50 mm round to be perforated. They have been described as resembling bloated frogs, not quite as big as a Human being, with four limbs and a tail. What appears to be sand filling the interior of their bodies is actually a mass of nanites. It's believed that Mimics have been created by another alien species to act as xenoforming devices, converting planets before the arrival of their mysterious masters. There are vents on a Mimic's body, from which they can fire projectiles known as javelins, which are shot with the force equivalent of a 40 mm round.

Mimics are hive-based organisms, each group consisting of a central Nexus unit and numerous Antennae units, which send signals to the Nexus. Their most extraordinary ability consists of rewinding time, which allows them to return to a previous point in time whenever they're killed, while retaining their memories of how they've been killed, to enable them to avoid that fate. This ability makes them practically unbeatable in combat. Only the Nexus is capable of rewinding time in such fashion, but the Antennae are also affected and signal for the Nexus to do so.

Appearances

 * All You Need Is Kill (オール ユー ニード イズ キル), novel, by Hiroshi Sakurazaka (2004)
 * All You Need Is Kill (オール ユー ニード イズ キル), manga, by Ryōsuke Takeuchi and Takeshi Obata (2014)