Barbara Streisand first appeared in the series 1 episode "Mecha-Streisand". Kyle finds a strange triangle object, which turns out to be one half of the "Diamond of Pantheos". The diamond was split into two separate triangles and hidden in different locations across the globe, but Streisand found one of the pieces during the shooting of My Fair Lady. When Streisand gets the other half, she transforms into Mecha-Streisand and destroys South Park. She is defeated, however, by Leonard Maltin, Sidney Poitier, and Robert Smith, who take the forms of the Japanese movie monsters Gamera, Ultraman, and Mothra respectively.
Streisand later appears in a somewhat updated form resembling Kiryu (she now has a brand-new CG appearance) in the episodes "200" and "201". When Tom Cruise is insulted by Kyle, Cruise calls together 200 other celebrities, and attempts to capture Muhammad for his "goo", which would supposedly allow them to never be made fun of again. However, when the Gingers interfere, Cruise is forced to unleash Mecha-Streisand on South Park once again. She is subdued this time by the Super Best Friends, who take advantage of her weakness to Neil Diamond music.