Hmmm.....well, its a stretch, but......many species of jellyfish are almost entirely clear, to the point that predators or people don't even see them until they're right next to them, if at all. The same goes for the tentacles; some species have long, nearly invisible tentacles (invisible like a ghost perhaps?) that can easily be overlooked by their prey or humans until its too late.
An example of this can be found in the lion's mane jellyfish, which can have tentacles as long as 90 ft (the largest recorded lion's mane had tentacles measuring 120 ft). Lion's Mane's are the largest species of jellyfish known to man, a native species to the waters of Japan, and are commonly recorded to being either reddish or bluish in color, so they could be the basis for a new jellyfish (as the man o' war jellyfish-- which, incidentally, isn't a true jellyfish-- was the basis of Tentacool/cruel)
Other species are so small that they simply 'ghost' right through nets put up in the water around beaches to keep larger species (such as the box jellyfish) out. The thinner tentacles of a Lion's mane can also 'ghost' through the anti-jellyfish nets on occasion.
Like I said, its a stretch, but I tried....