It relies on casting a number of (cheaply-costed) walls and other creatures with high toughness, and then using Phenax's ability to mill your opponent for a huge number of cards once you have a wall of creatures in play
If you want to improve the deck further and have the budget to do so, Arthur - Wizard's Apprentice is a very good card in an aggressive bounce deck
Etrata, the Silencer and Ramses, Assassin Lord are perfect additions to the 99 that support the assassin typal theme and get as many combat triggers as possible
The set has a whopping 360 cards to trade and collect, with over half of them being Shiny Pokemon
You can't go wrong with either flavor
Whats more, most of those events havent had a Stage-2 deck come close to winning, hence the concerns about the viability of those decks