Looking at that, and reading over the comments on the comparison entry, I knew I needed to make Barracuda more sheer and murky to mimic Bikini Bottom. For the sheerness, I needed clear, which was easy enough to find in my frankening drawer. For the murkiness, I wasn't sure; greyed green seemed the right direction, so I grabbed white and black for the grey part and a green from my stash. Here are the raw materials I used:
To make the franken, I poured a lot of the Barracuda into an empty bottle, added some clear, and then added the white, black, and green a few drops at a time. I'd mix it up, swatch on paper next to a swatch of Bikini Bottom, figure out what was missing, add that, swatch on paper again, and so on and so on. It was a process of trial and error, pretty much.
When I had something I thought was close, I moved on to swatching on my nails. First I put four coats of Bikini Bottom on one finger so I could see what I was aiming for. Once on the nail, I could see my franken was not sheer enough, so I added more clear (and cleaned off some nails so I could apply the new version). Still not sheer enough, so more clear, more cleaning, and I decided it was close enough. The franken only takes two coats to Bikini Bottom's four, so it's still not sheer enough to be a true dupe, and I think I could go a little more murky, too, but I think it has a very similar feel. (Somewhere along the way, I smudged the Bikini Bottom nail but failed to notice until I looked at these photos later.)
I'm tempted to work some more with this to try and get it closer, but there are so many other things I want to do, I think I'll leave it be. It was a fun experiment but since I do have Bikini Bottom, I don't really need to make myself a true dupe as well.