Professor Toad

"Well, all things considered, it could have been wors— Wait! Who are you? I've never seen anything LIKE you. Are you one of the Ancient Ones? Tell me!"

- Professor Toad

Professor Toad is a Toad who joins forces with Mario in Paper Mario: The Origami King. He is a college professor of ancient history, who also doubles as an archaeologist.

In the overworld, Professor Toad can not only decipher ancient text, but he can also use his shovel to dig up sand and dirt, sometimes revealing treasures; this makes him the only partner in the game to have abilities outside of combat. In battle, Professor Toad uses Dig This, dealing 24 damage to enemies in a hammer or jump formation. However, this attack sometimes misses. He is also the only partner who can rejoin Mario whenever he revisits the chapter he found him in.

Background
At some point prior to the events of The Origami King, Professor Toad began pursuing ancient legends, most notably the legend of Captain T. Ode, and the Scorching Sandpaper Desert's Sun Altar that guarded his preserved body. While staying at the hotel in Snif City, he managed to find some clues as to how to open the Sun Altar, placing some Sun Essence on it afterwards, but ended up causing a desert storm and getting eaten by a Paper Macho Mega Pokey.

In Paper Mario: The Origami King
Mario and Olivia manage to save Professor Toad by using the same clues he followed, and then destroying the monster that consumed him. Figuring that the desert is too dangerous, he decides to tag along with the two, insisting that they return to the hotel and examine its murals. After reading the ones in the hallway, and then the ones in the suite (provided they get the key from Luigi after winning a guessing game), the trio sets out to unlock the Fire Vellumental Cave, where Professor Toad decides to remain outside for the sake of his safety.

Once Olivia has gained the Fire Vellumental's power, she and Mario rejoin the professor, and the three set out to examine the four Toad Towers throughout the desert. After lighting the torches within each one, and also digging up some differently-shaped jewels to place in their eyes, the trio unlocks the Temple of Shrooms, where Professor Toad this time decides to tag along, albeit still expressing his cowardice at the faceless Toads they encounter. After solving a series of puzzles, he stands back to let Mario defeat the Hole Punch, destroy the yellow streamer, and free the sun, which automatically settles back into the sky.

With the sun back out, Professor Toad discovers that the Sun Altar has awakened, allowing the trio to access the frigid cavern hidden underneath. They find Captain T. Ode there, preserved in ice, before freeing him with the Fire Vellumental's power. Professor Toad expresses excitement at his quest now being complete, and the effects it will have on his career, but states that he cannot follow Mario and Olivia on the rest of their adventure, stating that he feels more at home in the desert.