After Jesse's sales pitch to Tuco goes wrong and he is badly beaten, Walt decides to pay Tuco a visit. After talking Tuco into inspecting his meth (which is actually a crystal of fulminated mercury) he feels he is not being taken seriously enough. His reaction to this is to hurl the crystal to the ground, causing a massive explosion, effectively destroying most of the drug lord's headquarters. After seeing the damage that a p*ssed off Chemistry Teacher can deal out, Tuco gives in. Walt gets his money and the promise of a future deal, while Tuco gets a brand new grudge.