At the height of his popularity in the early 70's, the Pink Panther was licensed out to Post, then a division of General Foods, for a brand of breakfast cereal. Basically, Post created a pink-colored variation of their long-running Toasties brand, their answer to Kellogg's Corn Flakes.
Now, I must admit that until today, I'd never even known this cereal even existed, flying under the radar as Post had acquired another license in 1971 that's still going strong today----the Pebbles line of cereals, endorsed by The Flintstones.
DePatie-Freleng (of course) produced the following commercial:
Needless to say, it didn't last more than a year.