Item from Breaking Bad by Vince Gilligan
Walt's slow-acting poison of choice — prepared twice, deployed once, and the weapon that finally killed Lydia through her own Stevia addiction.
Ricin is Walt's signature non-explosive weapon — a toxin derived from castor beans that he prepared twice during the series. The first batch was hidden in a cigarette for Jesse to use on Gus — it was never used, but Huell pickpocketed it from Jesse as part of Walt's manipulation. Walt used this to gaslight Jesse into believing Gus had stolen it. The second preparation was used in the finale — Walt swapped Lydia's Stevia packet with ricin at her regular coffee shop. Her pathological need for routine was her undoing. Walt's last phone call to her: 'I was there. I slipped it into that Stevia crap you're always putting in your tea.'
A white powder concealed in a cigarette (the ricin cigarette) or in a Stevia packet. Odorless, tasteless when mixed. The ultimate chemist's weapon — you don't need a gun when you understand biochemistry.
Also known as: Ricin, The Ricin Cigarette