This is the first Garfield TV special to be based on original content. The previous TV specials borrowed plot elements and jokes from the comic strip.
The boat that Odie and Garfield use to get to the haunted house is named "Carolyn" - a reference to Garfield creator Jim Davis's first wife.
While Garfield is flipping TV channels trying to find Binky the Clown in the opening scene, one of the channels features Orson Pig from U.S. Acres for a brief second.
Binky the Clown makes his animated debut in this special, before his appearance in the comic strip. He was previously first mentioned in the March 13, 1985 strip and first physically appeared in a series of strips one year later as the head clown of a circus Garfield runs away to and joins.
THUNDER - BIG THUNDER CLAP AND RUMBLE, WEATHER 02: Heard multiple times throughout the scene where the old man tells Garfield and Odie about the pirates burying the treasure.