I think it might be about a metaphor for how society tends to make the sex out to be rad. Maybe the people in the video only came to the pool so that they could do the hanky panky. The first two were all for what society expected of them, while the wuss girl was all like "naw" at first. The worm-like monster show how demonised the wuss girl sees people who are willing to bonk, and the ending could be the wuss losing their innocence. I dunno.
It's supposed to be a tribute to H.P.Lovecraft. The band (Dye) also has another song called Hole in the Ocean which is based on Salvador Dali's script for a Disney film.
I really enjoyed Dye Fantasy the first time I watched it. Reminded me of ****** dead space or some **** .
However, as much as I liked it, once was enough and I'm not clicking play on this.