Lucy in the Sky - S1.E2

Rogan, a smuggler contacts the Nemesis with information to sell. Allowed on board the ship, he brings Logan, his small childlike purple pet alien that unbeknown to the crew secretes hallucinogenic ooze. Slowly the crew become affected by the ooze and begin to see their own personal fantasies play out before their eyes. This episode had everything from giants in pink tutus to Jazz singers to Clark Gable!

Later when everyone is still recovering from the effects of the ooze, they find out that Rogan had his own objectives, which leaves Sally in an awkward position.