Actor Ken Weatherwax, who played Pugsley on The Addams Family series, has died.

His niece, Shanyn Vieira, confirmed on her Facebook page that Weatherwax died from a heart attack. He was 59.

After portraying the son of John Astin’s Gomez and Carolyn Jones’ Morticia Addams on the 1964-1966 Addams Family series, he lent his voice to the animated series in the mid-70s and later portrayed Pugsley Sr. in the TV movie Halloween with the New Addams Family.