"This is your base?" Sentinel Prime asked, looking around the factory that they had adopted as their new home.
"Yes," Optimus replied.
Sentinel made a noise that was somewhere between a snort and a laugh. He then proceeded to wander around, opening storage lockers and nosing around peoples' personal effects.
In the course of his explorations, he stumbled across the area that they had been using as a rudimentary sort of mess hall. Sentinel gazed disdainfully at their meagre supplies, then picked up a can of crude oil that Optimus had been saving for later.
"What's this for?"
"That's oil. We drink it, as it contains hydrocarbons that we can synthesize," Optimus said. "Actually, that one is-..."
Before Optimus could complete the sentence, Sentinel popped the can open and chugged back the contents.
When Sentinel was done, he slammed the can down on the nearest table, and wiped his mouth on the back of his wrist. "Ahhhh. I'm surprised - that was actually pretty good. I guess that this planet doesn't completely suck, after all." He gestured to the can. "What's this stuff made from?"
"Dead organics that have been slowly crushed for millions of years." Optimus smiled at him.
Sentinel gagged, then ran out the room.