Jr. Troopa

Jr. Troopa is a character that appears in Paper Mario. He is first met in the Prologue chapter, after successfully finding the Hammer and attempting to leave the forest. Unlike other bosses, Jr. Troopa is fought multiple times throughout the game, each time grants him a different ability.

Prologue
When attempting to leave the forest where Mario and Goompa find the hammer, Jr. Troopa attacks Goompa, and threatens to beat up Mario for going to his self-proclaimed "playground". With the assistance of Goompa, Mario defeats Jr. Troopa, who vows revenge.

Chapter 1
After defeating the Koopa Bros, Jr. Troopa hides in a nearby bush as Mario makes his way back to Toad Town. When he jumps out, he accidentally slides into the nearby river, and waddles back up, asking the player if they remember him. Jr. Troopa has learned to hide in his eggshell, which increases his defense by 1.

Chapter 3
As Mario leaves Boo's Mansion after rescuing the Star Spirit, a text box is seen, but no one is around. After exploring for a few seconds, Jr. Troopa meets up with Mario, offering another fight. This time around, Jr. Troopa has grown bat wings, and now has the ability to fly. After being defeated, and Mario makes it to the beginning of the forest, the camera pans over to a relieved Jr. Troopa, thankful to be out of the maze.

Chapter 5
After Mario rescues the Star Spirit from Lavalava Island, he and Kolorado board the tuna, ready to leave, when Jr. Troopa is seen swimming all the way there. Just as he reaches the island, the tuna has already left, which forces Jr. Troopa to swim all the way back to Toad Town. Once Kolorado parts ways with Mario, Jr. Troopa battles him, this time he has a spike on his head in addition to flying. However, due to him exhausting so much energy swimming back and forth, the game points out that his HP has been reduced by half (he originally started at 40.)

Chapter 7
After Mario leaves Shiver City for the first time, Jr. Troopa attacks him again, this time he traded in his wings and horn for a staff, one that deals an extreme amount of damage. After Mario defeats Jr. Troopa, his body becomes encased in a block of ice for a good duration of the chapter.

Chapter 8
After reaching the second trivia door in Bowser's Castle, Jr. Troopa interrupts the preplanned fight between Mario and the Koopa Bros., knocking out the latter and challenging Mario. This battle is somewhat different, as Mario fights Jr. Troopa's various forms throughout the battle, including the horned bat and magic staff. Once Mario beats Jr. Troopa, he leaves him alone for the rest of the game, but swears he'll be back.

Credits
In the ending credits, Jr. Troopa is seen having a magic duel with Kammy Koopa, but they accidentally shoot their magic at Bowser, who in return, breathes fire on both of them.