“Smashed,” by Drew Z. Greenberg
After what feels like the longest “previously on BtVS” in the history of Sunnydale, we find Buffy interrupting a garden-variety mugging. Spike jumps in, eager to help. He means to prove manliness, devotion, willingness to do the right thing and possibly even the American Way, but instead what he (conveniently) proves is that his chip still works, because he gets an agonizing jolt when he punches one of the muggers.
I’ve asked before, I think, but how does the chip know when he doesn’t?