Animated emote, emulating the OOOO emote, but as a Ruby Splashtail from Sea of Thieves. Sea of Thieves has been a part of the Twitch Prime drops often and the Ruby Splashtail seems to hold some kind of a significance as it's been used for previous events in sea of thieves.

https://seaofthieves.fandom.com/wiki/Ruby_Splashtail#Trivia