bufagin

noun

bu·​fa·​gin ˈbyü-fə-jən 

: a toxic steroid C₂₄H₃₄O₅ obtained from the poisonous secretion of a skin gland on the back of the neck of a large toad (Bufo marinus) that resembles digitalis in physiological activity

also : any of several similar substances from secretions of other toads compare bufotoxin