As a child, I knew him best as the dad in the Beethoven movies, and later from Great Muppet Caper, but as an adult, I know him best because of a little movie he made with Martin Short called Clifford.
It's somewhat an embarrassing thing to admit, because it was widely regarded in its day as one of the worst movies of 1994, but I must stand my ground and be contrary to that opinion because I thought it was hilarious. They showed it a lot on the Disney Channel in the late 90s (back when they showed other good stuff like Dinosaurs and Muppets Tonight), and back in the day I thought it was just weird and forgot about it.
Then I revisited it last summer, and was shocked at how much better it was than I remembered, and I wish people had given it more of a chance before dismissing it. In the film, Martin Short (who was 40 at the time) played a 10-year-old boy, but as a total, really bizarre caricature, and Grodin played his uncle, who had agreed to watch him while his parents were on a trip. Short played Clifford as a vindictive, vicious prankster who was constantly getting under his uncle's skin, and the film made me laugh so hard in the summer of 2020, when the world was a rubbish pile, and god knows, I needed that.
But in watching it again, I realized something else. As funny as I found Short's performance, the true revelation in the film was Grodin, because all of the funniest moments in the movie depended on his reactions to Clifford's behavior. He is eventually driven to madness, and watching Grodin go from his usual character to being provoked constantly by the most bizarre character I've ever seen in a movie was delicious. It took a specific kind of performer to know exactly how to play that part to milk the material for all it was worth and make a strange setup actually work. If you haven't seen it, beware that it isn't for all tastes, but if you do watch it, keep an eye on Grodin, because his tone of voice and facial expressions are worth the price of admission, even if you don't buy Martin Short playing a 10-year-old.
RIP indeed.