One of the first things you need to learn about a new format is what board sweepers are out there
17 Brimaz, Blight Of Oreskos Double Up Phyrexians Suggested Cards: Massacre Wurm, Progenitor Exarch, Norn's Inquisitor Although Brimaz, Blight Of Oreskos doesn't directly support any infect creatures, where Brimaz does play into the infect strategy is the ability to proliferate if a Phyerxian died
Blue Arwens Gift This is a fine card on its own, but whats interesting is the influx of legendary matters cards in March of the Machine and Tales of Middle Earth
With minimal energy consumption and a huge amount of damage for a stage one evolution, Primeape may be a worthwhile risk compared to the somewhat average card of Sandslash
You'll choose the modes and targets, if any, for that second ability at that time, and players can respond to that ability as normal