That's what I'd call them. You can't flick them off your finger.
A friend's mother was given a ton of toys to distribute on the Air Base. One of the kids got these stuck up her nose and had to go to the hospital to get them removed, so they had a lot of this left over. So I scored a cup of "Gazz It Super Modeling Compound". It looked to me like a big gob of strike indicators.
So I got home and started playing with it, and do believe this is a good find. They are little foam balls held together with some kind of elastomeric coating. I don't have my fly gear with me right now but put a cluster of 5 little balls on some 6lb fluoro and whipped it as hard as I could on a 6' light spinning rod. It didn't slip even a little bit. The coating acts kind of like that rubbery snap back stuff you sometimes find in packaging.
I don't think it would work as well in warmer temps as the stuff gets a little less viscous with heat. However it didn't budge when whipped around in room temp air. The little balls are in different sizes from about BB size to 1/3rd of that. Might also be good to tie with as it can be easily be trapped under and squished into other shapes like eyeballs or ant bodies. Mine came in neon yellow.
You can get them at the Dollar Tree.
[youtube]http://www.youtube.com/watch?v=b7i79_X35Co[/youtube]