Here’s a shot of my first “4-way tentacle control”. I can’t say enough about the DVDs from the Stan Winston School of Character Arts! I’ve watched most of 3 DVDs, and learned so much, including how to machine parts for the tentacle control, and how to 3D print parts for the eye mechanics. Here, I’ve combined the two by 3D printing the spacing discs (think “vertebrae”).
In the Stan Winston terminology, anything that looks like a tail that swings back and forth plus up and down is referred to as a tentacle control. This is the basic mechanism for the chest burster in Alien!