Heronicus

Heronicus is a character in Super Paper Mario who lives in Flipside in the houses behind Saffron's restaurant. He is a retired explorer who "knows much about other lands", with certain smells bringing back memories. After each chapter a different smell brings back a memory of the world Mario has just visited.

It is mentioned by Heronicus (at the end of the game) that he spent a part of his life trying to find a "Legendary pixl" and had a partner while exploring. When both found this "legendary pixl" there was a rock slide, Heronicus leaped into action and saved his partner...but the "legendary pixl" was killed in the incident. This is the reason Heronicus stopped exploring.

Heronicus also appears briefly at the beginning of Chapter 6, fleeing from the Sammer Guys.

Trivia
🇵🇲
 * On a shelf in Heronicus' home, there is the vase from Chapter 2-3, a MeowMaid-like relic, and a model of the two stone heads found in Chapter 4-2; atop his bookshelf, a dark rock from Outer Space, a totem pole from Downtown of Crag and a torch holder from The Underwhere can also be found. Heronicus additionally has a picture that may possibly depict a blue Squarp Hole, and Flipping in his home reveals another picture of a sandy, dune-filled expanse resembling Yold Desert (Curiously, this picture actually shows the background Yold Desert possessed in the beta version of Super Paper Mario).
 * Heronicus has high scores in the Flipside Arcade of 550000 and 80000 in Mansion Patrol, and 1000000 in Hammer Whacker.
 * It is mentioned in Flopside by one of the Flip-Flop Folk outside of the Flopside version of Heronicus's house that the person who lived there (presumably Heronicus's Flopped version) also went exploring for a legendary pixl. And there was also a rock slide, but instead of saving his partner, he saved the pixl instead. It is unknown where Flopped Heronicus went, but the pixl he saved was Piccolo (since Piccolo was inside of the house).
 * It is possible that Heronicus's exploration partner was Interchet,who he chose to save instead of the "Legendary pixl" (Piccolo's Flipside counterpart). Plus there is no Flopside counterpart to Interchet (Because Heronicus's Flopside counterpart chose to save Piccolo instead of his exploration partner, possibly Interchet's Flopside counterpart). Also the chest in the Flipside B1 Outskirts contains the Interchet card, but in the Flopside B1 Outskirts version of the  chest ,it contains the Piccolo card. This might also explain why Heronicus spent some of his free time at the Flipside Arcade.