What was playing at the Lorain Drive-in on June 18, 1969?

What was playing at the Lorain Drive-in Theatre on Route 6 on this day, 50 years ago? Why, it was a double feature of Mad Doctor of Blood Island, (in "blood dripping color”) and Blood Demon (which was only in “blood curdling color").

Here’s the over-the-top trailer. Looks like a lot of fun!

Although the human/plant mutants drip green blood in the movie, the stuff splattered all over the monster in the movie poster below looks pretty red to me.

Anyway, I wonder what the “mystic potion” was that was given to all of the Lorain Drive-in patrons? 

By the way, Angelique Pettyjohn (the female lead in Mad Doctor of Blood Island) had an interesting movie and TV career, including appearances on Star Trek and Get Smart (as agent Charlie Watkins).