To be honest, when seeing this, I remember how, in the "Choice Of... Games" game, "Choice of Robots", you are given all sorts of options on how to build your initial robot, including what power source they use. One of them (for the most hippy "humanity points") involves running the robot on a small diesel engine fueled by grease from the local fast food restaurant, which, the game notes, also makes the robots have the faint "comforting scent of french fries" at all times.
Ehhhhh....*Mechanical whiiiine**Clatter!**Jerk!*I'll take it.Whaaaaaaaaa!!?The transaction price is 25 million.*Squeek*
*squikie*
*squeeek...**Engine
revving**Engine
revving**Squeek*
*squikie*
*squeek*This is the limit of modern science.