Nanoreagent hydrocarbot

From Halopedia, the Halo wiki

Nanoreagent hydrocarbots, also known as Slop to military personnel, are a suspension of nanomachines that render nearly all carbon-heavy matter into usable fuel for the UNSC's ubiquitous internal combustion power plants, including the hydrogen-injected internal combustion engines used by the M12 Force Application Vehicle and the M274 Ultra-Light All-Terrain Vehicle.[1]