Sad news, indeed. After Robert Hegyes’ death earlier this year, we’ve lost another sweathog. Ron Palillo, aka Arnold Horshack from “Welcome Back, Kotter,” passed away this morning at his home in Palm Beach Gardens, Florida.

Tributes to Gabe Kotter’s most enthusiastic student poured in:

Raise a glass — and raise your hand — in Palillo’s honor.

RIP.