What is the name of Mario's first partner in Paper Mario (N64)?

Mario's first partner in the original Paper Mario is Goombario, a young Goomba from Goomba Village. He joins Mario shortly after the opening disaster and becomes the first partner available in the adventure.

After Bowser steals the Star Rod and lifts Peach's Castle into the sky, Mario is defeated and falls near Goomba Village. Goombario and his family help him recover. Once Mario begins searching for the imprisoned Star Spirits, Goombario accompanies him and introduces the game's partner system.

Goombario's signature ability is Tattle. In battle, Tattle reveals information about enemies, including their HP, attack power, and defense. Outside battle, he can also describe characters and locations, making him useful for players who want extra context about the Mushroom Kingdom. His field ability, Headbonk, lets him strike switches and interact with certain objects.

The other listed characters join later: Kooper is the second partner, Bombette follows in Koopa Village, and Parakarry becomes available during the Dry Dry Desert portion. Their later introductions are why they are sometimes mistaken for Mario's first companion.