Professor Kolorado's father is a Koopa who presumably goes on journeys like his son. He went to Hooktail Castle in an attempt to destroy Hooktail, but became trapped in the castle, so he wrote a note, saying that Hooktail's weakness was a cricket, and that she would use any trick to save herself from ultimate doom, and that no one should give in to their kinder nature and fall for her tricks. He died in the castle sometime after writing the note, and his bones could be seen. His shell appears to be blue.
In Paper Mario: The Thousand-Year Door, Mario and Koops found his bones and read the letter. Koops initially thought him to be his father, whom he believed to have been killed by Hooktail, until he read in the note that his son was Kolorado.