What a Long, Strange Trip It's Been is the twenty-eighth episode of Godzilla: The Series, and is the seventh episode of season 2.
The episode opens with Godzilla defending H.E.A.T. headquarters from a giant mutated germ called Bacillus. Godzilla is able to defeat it, but a wound gained in the fight becomes infected by the bacteria, and N.I.G.E.L. is sent into the wound where it finds miniature (about N.I.G.E.L.'s size) Bacilluses in Godzilla's system. Mendel Craven, who was soused in the bacteria during the fight begins to develop the same symptoms as Godzilla. Elsie Chapman decides that she can make an antibiotic for Craven, but to help Godzilla they will need to enter his body to free his cerebral cortex from the bacteria to allow his natural antibodies to properly defend against them. Nick and Monique volunteer to go inside, but while in his bloodstream they are attacked by Bacilluses. They are forced to abandon the sub due to the damage they cause to it. Monique tries to abandon the mission after the loss of the sub, but Nick suggests that they ride through Godzilla's pulmonary artery and into the brain through the heart. Elsie is able to synthesize a cure with the help of Randy Hernandez, and they put it to use on Craven, but before they can record results, Bacillus attacks the H.E.A.T. Seeker, but Craven, who is already feeling better is able to steer it away from danger. Nick and Monique are able to reach the Cerebral Cortex, and notice the bacilluses are congregating on Godzilla's brain stem. Monique promptly shoots them off, while the main Bacillus heads for the New York reservoir. Elsie then uses the formula for the antibiotic to create a stronger version to destroy the Bacillus before it can contaminate the city's water. Godzilla recovers, and comes to fight it, but Craven is able to deliver the antibiotic before he can. Nock and Monique are then sneezed out as Godzilla prepares to head home.