Godzilla
Godzilla (1954) is a Japanese monster movie, directed by Ishiro Honda, starring the giant monster Godzilla. This movie spawned several sequels including an flopped American remake in 1998.
Matt Groening is a fan of the original Japanese film series.
References
In the 'Treehouse of Horror VI episode of The Simpsons in the segment "Attack of the 50 foot Eyesores", after Homer steals the Lard Lad's giant doughnut, he gets struck by lightning and comes to life. Then, he pulls his feet off the ground and stomps into the middle of the street, and emits Godzilla's trademark roar.
In The Simpsons episode "Thirty Minutes Over Tokyo" the family's flight home is briefly interrupted by a monster attack on Tokyo, featuring Godzilla and other Japanese film monsters: Gamera, Rodan, and Mothra.