Barking Bibliophile or Bewildered by Beasts? Unmasking Sophie's Literary Prowess

Has Sophie Seen it All? Unicorns and Squirrels Up the Ante in Today's Hilarious Dog Eat Doug Comic!

Funny Dog Comics: Baby Doug and Pupy Sophie sit under a tree in the yard. Sophie asks, "Ever wonder if you've seen everything there is to see?" Off panel someone yells, "Yeehaw!"
Funny Dog Comics: The squirrels race past riding a sparkling unicorn. One of the squirrels yells, "I LIKE SHORTS! THEY'RE COMFY AND EASY TO WEAR!"
Funny Dog Comics: Sophie and Doug have shocked looks. Sophie says, "Never mind."

Where Do You Find Squirrel-Powered Unicorns? Unravel the Wacky Wonder of Today's Dog Eat Doug Comic

One of my favorites. Also, the “I like shorts” line is an easter egg from some cartoon, and now I can’t remmeber. Anyone recognize it?