So, I did manage to make a character for the contest. I thought I was going to do well.

Then it turned out that there were three separate instances of the theater where the contest was held and some people went all out. Oh well. At least I got the Strong Swimmer award and got to see the swim animation in the air. I also asked around and found out about some swim-like travel powers, so it was helpful from that standpoint.

Since they didn't have a water or fish related hero archetype, I wanted to make my character with a power that I likely wouldn't have otherwise tried. I went for the Rockstar archetype, which combines sweeping swings of larger melee weapons (I went with an electric guitar, though I hope to unlock the trident option when I can find it) and either pyrotechnics or sonic effects (I am leaning towards the sonic ones for a sort of rock star siren). I also picked the Heroic Flight travel power, which has swimming motion and leaves a reddish trail. And I named the character Dash on the Rocks to combine that rockstar theme with a siren element.

Here is the Twitch video of the various costumes everyone came up with, which are quite elaborate. They start showing the in-game stuff and the costumes around the 5:42 mark. Dash on the Rocks is at 43:49 or so. The announcement of the honorable mentions is at 51:19. The announcement of the winners is at 59:10 or so. At around 1:03:20 or so they started making the winners grow to giant size one by one and have all the other contestants fight them. I did pretty well with the first couple fights, but the sea ghost and the underwater dinosaurs wiped the floor with me repeatedly.

https://www.twitch.tv/videos/929727312