This article contains spoilers from last night's episode of Mom.Death is subject sitcoms seldom touch. When they do, it's often presented in a comic light. Think Rachel Green's evil boss getting plowed down by a cab, or Gloria getting dolled up in an oversized black veil for Phil's mom's funeral on Modern Family.That's what made the character death on last night's episode of Mom, which has dealt with the subject before, so unexpected and shocking. The character wasn't an old relative who'd never been on screen, or someone fans were rooting to get rid of. She was a vibrant young woman struggling with drug addiction, plunging the show into some dark territory.Last night's episode saw Emily Osment 's character Jodi, a recovering teen addict taken in by her AA sponsor Christy ( Anna Faris ), die from a drug overdose. The show ended with a PSA from Faris and co-star Allison Janney urging viewers with addiction issues to seek help.Fans were quick to react to the death on social media. Even Surgeon General Dr. Vivek H. Murthy, who appeared in the show's PSA, chimed in.