Alex Vreeke is a new character from Jumanji: Welcome to the Jungle. His avatar is Seaplane McDonough. Mason Guccione plays the teenage boy who played, and was trapped inside, the Jumanji video game for 20 years. He is credited as "Young Alex". Colin Hanks portrays adult Alex Vreeke after he returns to 1996 and appears 20 years later, changing history as a result.
In 1996, in Brantford, New Hampshire, picking up from the previous film's ending, musician teenager Alex Vreeke receives the Jumanji board game, found by his father on a beach after it was thrown over a bridge by Alan Parrish and Sarah Whittle in 1969. When Alex receives the game, he asks himself, "Who plays board games anymore?". The game, sensing Alex's interest in video games, magically transforms its game-board into a video game cartridge which catches Alex's attention later that night. As he plays it, he is teleported into the game. The uncertainty of Alex's fate led to his father losing his faith and the house being abandoned for years.
Twenty years later in 2016, four students in Brantford High School are placed in detention together: Spencer Gilpin, Anthony "Fridge" Johnson, Bethany Walker, and Martha Kaply, who find Jumanji, they each are transported into the game. Along the way the group starts working together to obtain a clue from a snake at a bazaar but are cornered by Van Pelt's men. They are rescued by Alex, the fifth player, whose avatar is a pilot named Jefferson "Seaplane" McDonough. Alex, thinking he has only been in the game for a few months, learns he has been in the game for twenty years. Recuperating in a tree house built by Alan Parrish, the newcomers vow to help him return home. Working together, the group breaks into a transportation shed, commandeering a helicopter to fly to the jaguar statue and return the jewel. Upon landing Alex loses his last life after a mosquito bites him, but Bethany performs CPR in time and saves him by transferring one of her lives to him.
The game ends with all the players on one life each and they all call out the game’s name, with Van Pelt disintegrating into many rats, and Nigel allowing the players to revert to their former selves and return to the real world, though Alex does not appear with them. On their way to the Vreeke household (once the neglected home of Alex's father "Old Man" Vreeke), they discover it has been restored. An adult Alex appears; he returned to 1996, and history was changed. He is now married and has named his eldest daughter after Bethany out of gratitude for saving his life.
- Alex's role essentially serves as a parallel to that of Alan Parrish, down to going missing for 20+ years, his family's lives after the disappearance effects and time being reversed when the game is won, even finding a treehouse made by Parrish. The differences between Alan and Vreeke he was trapped in Jumanji for an extra 6 years, while the latter was trapped 6 years less. Also for Alex, he is simply sent back in time to 1996 and rewrites his part of history by never getting trapped. Unlike with Judy and Peter Shepherd, Alex being returned to his own time does not undo the game played by the other teens nor do they lose their memories.
- The game console used in the Jumanji video game is actually Alex's console. The board merely transformed itself into the game cartridge Alex plugged into his console.