quarantine 'em

Still with me here? * Smithers has a cast-iron alibi - he was watching "Pardon My Zinger" at 3pm * Marge is on camera at the time of the shooting. This is enough for us as viewers * Sideshow Mel's weapon of choice is a flick-knife, which potentially rules him out as a shooter

Now let's re-examine the town hall seen. "Oh, you all talk big," Burns says, "but who here has the guts to stop me?"

So. If we've settled on Burns being shot with his own weapon, the "I think you'd better drop it..." dialogue is puzzling. What, if not a gun, was the assailant carrying, and why did Burns want them to drop it?

Earlier in the episode we saw Burns express his love for taking candy from a baby. Maggie's a baby, she must have had candy. The pieces fit!

Several insane wildcard theories also made the rounds, most memorably the "Superdude theory" which suggests that Burns was somehow shot by the Springfield Elementary hamster who is found dead at the beginning of the episode