When I was very young I got to watch and mentally live with some great “monsters”, like the terminator (from the first movie), and the alien (from the first two movies). These creatures gave me endless nightmares, and the more nightmares I had, the more I had to rewatch the movies. Those two monsters, along with the predator, shaped what a frightening, fantastical creature was for me.
I recently came across some short clips on youtube with some of the people who worked on the original creature effects talking about their work. Here’s Stephen Norrington talking about working on the small chest-burster creature they used when filming Aliens. It’s essentially a giant tentacle with teeny teeny arms.
And here’s a clip on the creation of the predator costume for Predator 2. The costume was sculpted from clay, then moulded, cast and painted.
And because it’s so on topic: Predator, the Musical (contains singing and graphic violence)!