Fringe: Season 1, Episode

1 - :

A Massive Dynamic employee, Mark Young (Ptolemy Slocum), jumps out of a window when he believes he is being attacked by butterflies. Olivia's connection with John Scott leads her to breaks in the case, but she becomes fed up with his manifestations and decides to return to the sensory deprivation tank to rid herself of them. Meanwhile, Peter's past catches up with him when his enemies find out he's back in Boston. Walter discovers that a hallucinogen produced by frogs is being used to literally scare victims to death, and the frogs are tracked to a suspect, George Morales (Yul Vazquez) with whom John was involved. Morales points to Massive Dynamic as the real culprit and tries to make a deal to testify, but is himself poisoned by the hallucinogen before this happens.