a little brain massage

Yeah, I started out trying to do it by shape-tweening between various keyframed poses, but that was hard-as-heck, with lots of shape hinting--just a pain. Here's my simple trick:

Start by drawing a wavy line (make a good, long one; you can crop down to get the number of wiggles you want). Set the path thickness depending on how fat or thin you want your vine/tentacle.

Make it a graphic symbol. Then motion tween it from left to right (or R to L).

Make a mask layer with a rectangle; size it to trap the middle of the movement (clipping off the ends of the line) until when you play the move (with Loop Playback turned on) you get a good continuous illusion of a wiggle inside the rectangle.

Adjust by scooting the keyframes further apart or closer together and adding frames to get the speed of wiggle you want.

Then select the whole timeline of the motion tween and hit F6 to convert all the frames to keyframes.

Then turn on "Edit Multiple Frames"; adjust the slider to get all the keyframes in range; select all and hit Control + B to break all the symbols up.

Then convert all the lines to shapes. Then with everything still selected in "Edit Multiple Frames" view use the marquee tool to select and clear the ends (use the boundary of your rectangle mask as a guide).

Then (everything still selected) you can use the Distort mode of the Free Transform Tool to add perspective and/or a tapering to the vine.

Then copy/paste these frames into a new symbol. That's about it. From there you can drag this into a scene, and by tinkering with the color effects, scale, start frame, etc. you can get a lot of variety out of one element. (That's two different vines in my doodle, actually).

Hope someone finds that useful. I was kind of proud of figuring it out. --t