There are five event decks, one mono-black and one with black and each of the other four colors. Each has nine Yargles and an assortment of other cards. You pick one and play Bo1 games. Everyone has two emblems, one that makes frogs cost 2 less, and one that says when a frog ETBs, you may sacrifice a creature to draw a card and have the frog gain all the abilities of the sacrificed creature.
Might be worth pointing out that the green and blue decks have a few more frogs than the others.
I picked the black/green deck because it had Yargle and Multani in it. Went 2-1. Best combo was when I sacrificed [[Nested Shambler]] to a Yargle, then sacrificed that Yargle, which now had the Shambler's ability, to [[Uurg, Spawn of Turg]].
[[card name]] to call