alien An extraterrestrial lifeform. A creature who is clearly not from planet Earth.Don't use this tag for alien characters who look indistinguishable from humans. Tag what you see, not what you know.For the aliens from the Alien series, see the xenomorph tag. 不要将此标签用于看起来与人类没有区别的外星人角色。标记你所看到的，而不是你所知道的。