Fish

Using it puts a Baby Penguin at your heel. It waddles after you on the ground and pulls out a jetpack the moment you get airborne or start outpacing it, so it keeps up during hook swings and mount travel instead of dropping behind and blinking back to you. It is company and nothing else, no stat, no help in a fight.

Frozen chests in the ice caves are the classic source, but crates fished out of the snow biome are the source you can actually control. Chests are a fixed number per world and get looted once, while you can sit at a pond and farm crates until it drops.