It was the episode where Walter shaved his head. It was the episode where Heisenberg arrived. Attempting to sell their new methamphetamine into the market, Jesse approaches local drug lord Tuco with the product... and is beaten up for his efforts. Undeterred and with little to lose, Walter decides he needs Tuco's respect. Approaching him laden with more meth, he reveals to have actually brought Mercury Fulminate, a crystallised substance that explodes upon impact, as he dutifully demonstrates. Threatening to blow them all to hell, Walter bargains the sale of his product at a premium and takes the first steps down the long road to becoming Scarface.