Pretty sure I saw this as a kid and it scared the daylights out of me

The movie was made before I was born, but I do recall when I was about 5 years old my parents leaving me with a babysitter. And I remember the baby sitter watching this movie on television that I remember being about people either on a military base or in a hospital and they were under attack by these shreiking black creatures with tentacles. I remember it having the vibe of a classic TV show, either Star Trek or MASH.

Needless to say, as a 5 year old the movie scared the bejesus out of me. Gave me several nightmares actually. Unfortunately, I never remembered what the title was.

Now, several decades later, I somehow started thinking back to that movie that scared me so much as a kid. And I was able to narrow down what that movie might have been.

I think this movie was it.

They actually have the entire movie up on YouTube. The one scene I remember most vividly was where a creature comes up from behind the wall and scares a female character, perhaps a nurse. And there's a scene about 50 minutes into The Green Slime that very closely matches my recollection.

As I suspected, as someone in his 30s, watching the movie now it looks like pure camp, and the monster looks laughably bad. But I don't know if I ever was as terrified of a movie as I was of this movie when I first saw it.