<Li> Morgan Turner as Martha Kaply, a teenage girl at Brantford High School who goes to detention with Spencer, Fridge, and Bethany, for objecting to physical education class and disregarding her teacher as a result and Spencer's love - interest . She is credited as "Young Martha". </Li> <Li> Mason Guccione as Alex Vreeke, a teenage boy who played, and was trapped inside, the Jumanji video game for 20 years . <Ul> <Li> Colin Hanks as Adult Alex Vreeke </Li> </Ul> </Li> <Ul> <Li> Colin Hanks as Adult Alex Vreeke </Li> </Ul> <Li> Colin Hanks as Adult Alex Vreeke </Li>

Who plays grown up alex in jumanji welcome to the jungle