Common Side Effects episode 7 ending explained: Does Marshall die?

Common Side Effects episode 7, titled Blowfish, premiered on Adult Swim on Sunday, March 9, 2025. Following up on last week's cliffhanger, the episode immediately picks up with Marshall being killed by the assassin sent out by Jonas. Aside from that, the episode also features some huge developments for Frances as she goes through a huge loss.

Warning: Spoilers for Common Side Effects episode 7 to be mentioned. Reader discretion is advised.

Common Side Effects episode 7 begins with Christopher saving Marshall from the assassin. However, while he does survive the attack, the episode does indeed prove to be a fatal one for him. This comes as he dies at the end of it and the show leaves viewers with another cliffhanger about where the show is going to go next.

How does Marshall die in Common Side Effects episode 7?

In Common Side Effects episode 7, after Christopher saves Marshall from the assassin, the prison king tells him he owes him. Christopher then tells Marshall that prison is his life now and that he better make himself useful. This leads to Christopher having Marshall over in his cell and telling him how people will continue to come after him, and that he rather serve his needs if he needs protecting.

Christopher then asks Marshall to treat his buddy but to do that, Marshall would require a toxin that can only be acquired from a pufferfish. When reading up about things in the library, Marshall is visited by a stranger who positions herself as his ally. Saying that she used to work with the DEA but then quit, she reveals that she knows about Marshall's mushroom but hasn't been able to grow it back.

Marshall then realizes that Socrates is the key to the mushroom being able to grow and stage a prison breakout. He asks the stranger to bring him a vial of the puffer fish toxin - as it can prove lethal when the right amount is used.

Once Marshall receives the vial, he basically tells his prison cellmate that he is going to die and ingests the tox as Common Side Effects episode 7 then cuts to credits with his lifeless body on the screen.

Is Marshall truly dead?

While, as of now, Marshall is indeed dead - he will of course return next week. As mentioned in the episode, he needs to desperately get out of prison, and for that, he will have to first die which ends up leading to his plan. It's possible that going forward this will lead to Marshall being brought back to life once he is out of prison.

Even in the mid-season trailer for Common Side Effects, Marshall was showcased to have more scenes in the show. So for those worrying that they won't get to see Marshall in the future - well, don't. Marshall is surely set to return in the upcoming episodes even if he did die in Common Side Effects episode 7.

Frances' mom dies in Common Side Effects episode 7

Common Side Effects episode 7 also features a cold open where Frances' mom can be seen climbing a tree and falling off it. As the episode goes on, Frances can be seen going through many hardships. Cecily threatens her for not giving up the blue mushrooms and also thinks that Marshall probably hates her now too.

Her mom's death does send her over the edge as she wonders exactly what to do going forward. However, after the funeral, she decides to go all in on her new persona, knowing that she is doing the right thing and that Marshall probably didn't even plan what to do with the mushrooms.

However, Common Side Effects episode 7 sets her up for a crucial role as Jonas and Cecily seem to be doubting her when it comes to the mushrooms.

Copano and Harrington have bad experiences with their new partners

In the previous episode, Copano and Harrington were split up and Common Side Effects episode 7 focuses on them not having a good time with their new assigned partners. Both go through a drug bust and see the incompetency of their previous partners which leads them to miss each other.

However, at the end of Common Side Effects episode 7 they are reunited when Harrington goes down to meet Copano. There she asks him about whether he was able to figure out what happened with Marshall and he reveals that the decision had to have come from the top brass.

For further updates on Common Side Effects, stay tuned with us.

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