Jonathan Frid was known to those of us of a certain age as Barnabas Collins - a vampire - from TV's Dark Shadows. He passed away April 14, 2012 of natural causes in a Canadian hospital. Some sources say he passed on April 13, 2012
Jonathan has a couple Cowsill connections. First, the Cowsill kids - like most of us - were loyal watchers of Dark Shadows. June 1970's 16 SPEC held an article that quotes John as saying "And, needless to say, Dark Shadows is one of my favorite TV shows. Jonathan Frid is just too much - he's my kind of spook!" Barry also stated in a November 1969 16 Magazine article that he was also a huge Dark Shadows fan.
The second known Cowsill connection is when Bob and Barbara were on the same episode of Generation Gap with Jonathan. Barbara instantly knew his name and character.