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If you’re wondering whether the Kremlin has pulled another poison out of its arsenal of secret toxins, you’re not the only one. Kremlin nemesis Alexei Navalny was taken to a hospital from his jail cell this weekend after authorities claimed he had an “allergic reaction,” leading some to wonder if he’d been poisoned. It’s unclear yet whether that’s the case but poison is a historic go-to weapon for Russian intelligence services looking to silence dissidents—a weapon with a long and bizarre history involving poison umbrellas, gas guns, and bee turds.

The poison umbrella: Georgi Markov is probably the most famous victim of a Soviet assassination toxin because the attack against him reads like something out of a James Bond novel. The dissident Bulgarian playwright’s radio broadcasts had been a thorn in the Bulgarian government’s side and in 1978, Bulgarian intelligence operatives poisoned him with a pellet of ricin toxin shot into his leg by an umbrella injection gun. Authorities might have simply chalked his death up to natural causes rather than murder had Markov not aired his suspicions about being poisoned to hospital staff in his final moments.