The phrase “low energy” is normally used as a pejorative meant to imply lethargy or sloth. But for the mysterious lifeforms that lurk deep under the seafloor of Earth’s oceans—a sunless habitat with hardly any fuel sources—being “low energy” is a matter of survival. Now, a team of scientists has discovered that these otherworldly creatures “subsist at energy fluxes lower than have previously been shown to support life, calling into question the power limit to life,” according to a study published [Bradley, et al. C-DEBI Contribution 534] on Wednesday in Science Advances.