Infinite creature ETBInfinite copies of a specific planeswalkerInfinite creature tokens
How it works
Cast Jace by paying 1. Jace enters the battlefield with six loyalty counters due to Doubling Season
Activate Jace's third loyalty ability by removing five loyalty counters from it, creating four nonlegendary copies of Jace that enter the battlefield with six loyalty counters each due to Doubling Season.