Duckburg's Catapult and Frog Thor
One of the most beloved storylines in Thor history is the time Loki turned the Thunder God into a frog, who, by virtue of still being Thor, ends up being a 6'6" Frog of Thunder when he lifts Mjolnir, the magic hammer.
In the first issue of the storyline, Simonson dedicates the story to "Catapult, Carl Barks, and all the other heroes and villains of Duckburg." I was wondering who Catapult was, since I've been reading the Carl Barks collections put out by Fantagraphics, and I haven't run into any character named Catapult. So I looked it up and it turns out Catapult is from a 1958 story called "Old Froggie Catapult." In the middle of a storm, Donald Duck, Huey, Dewey, and Louie get a knock on their door and it turns out to be a frog. Not an anthropomorphic talking frog the way they're basically humans but in Duck form. Just a frog.
Frog jumping is Duckburg's most popular competition (in this story anyway), and it happens on a barge. Unfortunately, a typhoon hits, putting everyone in danger, so Donald sends Catapult on his way to Grandma Duck's house to send a message.
Walt Simonson is a big Carl Barks fan, and he even did drawings that ended up being on the endpapers of a Carl Barks hardcover collection in 1981:
Here's a drawing of his with Donald Duck and Uncle Scrooge, with a rooster from Plain Awful and an animal I feel I should recognize, but don't. (So if someone knows, tell me. Edit: It's the Lemming with the Locket. Thanks, Unca Walt!)
As for Frog Thor? Thor's frog friend Puddlegulp, once a man named Simon Walterson (get it?), found a sliver of Mjolnir and struck it on the ground, turning him into Throg, wielder of Frogjolnir, member of the Pet Avengers.
That's all quite a legacy for what started out as a tribute story to Catapult and Carl Barks and turned out to be one of the most beloved stories in the annals of Marvel history.