So Jake posted this 12 hours ago. It’s pretty much the same previous photo but zoomed out.
I don’t think it’s a perk. Since Jake said they’re creating this “big update” I’m thinking it’s somewhat going to be really different. And it would literally make no sense if Jake posted a perk as a teaser for Pixel World’s big update.
From my point of view, it kind of looks like a card game of some sort. It reminds me of this:
Also, someone has suggested a card game for Pixel Worlds before (I can’t recall their name). If I remember correctly Dev/Jake said that it would “take a lot of time if they do plan to implement this but the staff does want it to be in-game” and this update DID take a lot of time for the devs to develop 
is it a coincidence…? These are just my accusations, I could be wrong though.
Anyways, if it is indeed a card game, I hope that it will be fun and somewhat different than the other card games. Kind of like Adventure Time’s Card Wars game or Club Penguin’s Card Jitsu (if anyone knows what those are) but if it’s not, then I’m very much excited to see what the update is about! 