I know not relevant to this level. Just thought I'd better point that out before I get a vine of answers off on that rather than my question. This just happens to be level I was looking up when I thought I'd ask about it. I'm hoping someone can help as it drives me crazy that I can't figure them out.

What is the key to the tentacle pods? I can't figure out trick, if there is one, to opening them for the super jellies. It seems random, is it?