Toad-eater

A charlatan's assistant, whose job was to eat (or pretend to eat) a toad, so his master can demonstrate an aptitude for saving people from poisoning.

“’I want to ask you—please let this remain between us,’ Styopa begged obsequiously.

‘But of course, of course! But naturally, I cannot vouch for Khustov.’

‘So you know Khustov too?’

‘I saw him at your office yesterday, but a single glance at him is enough to see that he is a scoundrel, a gossip, a toady, and parasite.’

‘How true!’ Styopa thought, amazed at this brief, sharp, and accurate description of Khustov.”

Mikhael Bulgakov, The Master and Margarita (1928-1940).