That was over 29 years ago in 1992.
Today he is 50, and has starred in 89 movies in total, 75 since Encino Man was released.
In Encino Man, I think Sean Astin looks:
Encino Man scores 5.6 out of 10 on The Movie Database.
Sean Astin's first acting role was as 'Brian Reynolds' in Please Don't Hit Me, Mom, released in 1981 when he was 10.