In this picture, Kaylee is completely alone at night inside Serenity's cargo bay, stacking freight boxes. As sweet and peaceful as Kaylee normally is, for the moment she is deeply into a revenge-fantasy about terrorizing Jubal Early, the rapist from “Objects In Space.” She wants to grab Early with the mech's claw and squeeze until he pops!

THAT IS AWESOME! I can't wait to see her use that thing!

Just a revenge fantasy? Heck, give it to her for real! I'd love to see the sort of situations where that might be useful.

Is it powered by a miniaturized arc reactor?

AgentOmega asks, “Is it powered by a miniaturized arc reactor?”
Kaylee would love to make the mech self-contained but reactors are very expensive. The next best solution would be a turbine driven generator, like on the mule. But the exhaust from the turbine pollutes the air inside the cargo bay when Serenity is in space. The exhaust would make the whole ship stink!

Kaylee's solution is in the picture: the smaller of the two cables running down the right leg of the mech is an armored electrical cable powered by Serenity. There is a small battery on the back of the mech to make it possible to disconnect from Serenity for a few minutes. That's the best that Kaylee can do on a budget and buying parts from a junkyard.

Shortly after this picture was made, Kaylee tripped over her extension cable while pretending to drop kick Jubal Early out the airlock. The noise when the mech fell to the deck woke everybody. Mal came downstairs to say, “Turn that damn thing off and go to bed, Kaylee! It's 3 o'clock in the morning.”

Love the pic, love the story behind it.