I used to have one of those pans many, many years ago - my sister loves rabbits and I’d make her one every year for Easter. I remember the directions said denser cakes worked better and recommended pound cake for it.
Thanks Jeanne, that’s the info I was looking for. I remember trying a teddy-bear mold when I was in Jr High School, using a cake mix. The whole thing slowly collapse under the weight of itself, over the day. Very sad.