Snap, Crackle, Pop Kelloggs 1933

Snap 1937

These three little gnomes were the first and longest-lasting characters to represent a Kellogg's product. Artist Vernon Grant drew the early gnomes. They were also the first animated characters to ever appear in a cereal commercial.

Snap! Snap! was born in 1933. Snap! is the oldest and is a good-natured leader. He wears a baker's hat.

Pop! Pop! (1941) is a comedian. He wears an old-style military hat.

Crackle! Crackle! (1941), somewhat of a know-it-all, gets caught in the middle, trying to keep order between the other two. Crackle! wears a red-striped stocking cap.
It is rumored that a 4th, short-lived, character named "Pow" was introduced in the mid-1950's.
In 1949 Snap! Crackle! and Pop! magically changed from gnomes with huge noses and ears to more human-looking creatures with more proportional features. They continue to evolve. As fashions change, so do their costumes. Their hair also grows long or is cut shorter at times.
A Frankenstein monster and a skeleton appeared with Snap, a frightened Crackle, and Pop in this special 2001 Halloween box of Kreepy Rice Krispies. Halloween 2001