In "Roy Rogers McFreely", Roger first starts singing "El Perro" after Stan swallows all the horseradish. Later in the episode, the song is played during the car chase between Roger, Stan, Greg and Terry. Then, at the end, Roger dances under the motion sensor light, while Stan is watching him.

The song is originally performed by Cilantro (who is actually personified by Dan Navarro), but it seems that it has been made up just for the show.

Stan would reference and whistle "El Perro" again in "Stan's Night Out".

Lyrics

El perro, el perro, es mi corazón,

El gato, el gato, el gato no es bueno.

Cilantro es cantante,

Cilantro es muy famoso,

Cilantro es el hombre con el queso del diablo.

El perro, el perro, nunca sin razón,

El gato, el gato, el gato es obsceno.

Cilantro es caliente, Cilantro es cariñoso,

(Francine is vacuuming)

... nunca sin razón,

El gato, el gato, el gato es obsceno.

Cilantro es caliente,

Cilantro es cariñoso,

Roger : See you later, boys!

... mejor que su esposo.

English Translation:

The dog, the dog, is my heart

The cat, the cat, the cat is not good

Cilantro is a singer

Cilantro is very famous

Cilantro is the man with the cheese of the devil

The dog, the dog never without reason

The cat, the cat, the cat is obscene

Cilantro is hot

Cilantro is affectionate

... never without reason

The cat, the cat, the cat is obscene

Cilantro is hot,

Cilantro is affectionate,

... better than her husband