The Onos is the highest level alien lifeform in Unknown Worlds' debut FPS/RTS hybrid, Natural Selection. Evolving to an Onos requires 75 resources, independent of your current life form.

The Onos functions primarily as a tank, distracting the marines for other lifeforms and soaking up bullets like a sponge in Arizona rain.

In the current version of Natural Selection, Oni have 950 hitpoints and 600 base armor (this is much larger than any other combatant). It is not uncommon for three decently equipped marines to get utterly dominated by a solitary onos. Yet despite its apparent strength, the onos is a juicy target and is extremely vulnerable to traps, heavy machine guns, jetpacks, and long corridors. Due to its heavy price tag and late-game appearances, combined with its relative worth, competitive 6v6 Natural Selection matches rarely contain an Onos.

Attacks:
-Hive0:Gore:Standard melee attack, 90 dmg
-Hive1:Devour:removes a marine from gameplay, dealing time based damage until the marine dies
-Hive2:Stomp:Stuns a light or heavy marine within range
-Hive3:Charge:Increases speed and deals contact damage while engaged