Elmo's Grandpa

From Muppet Wiki

Elmo's Grandpa has two grandchildren, Elmo and Daisy. He lives on a farm with Elmo's Grandma. Elmo visits him in the 1990 Sesame Street book Elmo Gets Homesick.

He returns the favor 18 years later, visiting Sesame Street in the 2008 book What's the Word on the Street?