What is your first Horror Film?

[RCMerchant]

...that you ever seen? 

Mine-
I saw FRANKENSTEIN MEETS THE WOLFMAN on TV in 1967. I was 5.
At a theater- PLANET OF THE APES (1968). Unless you don't consider that horror and more sci-fi. Then it would be WILLARD (1971) at the Strand in Paw Paw, Mich. I was 9.

[claws]

The Last Man on Earth (1964)

I didn't see this at the theater, but years later on TV. I was about 3 or 4 years old. The film traumatized me and gave me nightmares.

Theater:

Let's Scare Jessica to Death (1971). Not during its original run; this was again years later when I was about 6 or 7 years old. And yes, the film gave me nightmares. The ending was too intense for me, so we had to leave the theater.