This clever loop relies on a self-sustaining cycle of shrinking and growing, fueled entirely by Hapatra, Vizier of Poisons sitting quietly on your board to reward every single counter placed. You start with Grim Poppet and Sakashima's Student—which has entered as a copy of Grim Poppet—each loaded with its own reserves of -1/-1 counters. By stripping a counter from Grim Poppet to place one on Sakashima's Student, and then immediately returning the favor by having Sakashima's Student shoot a counter back at Grim Poppet, you ping-pong the counters back and forth indefinitely. Hapatra watches this endless crossfire and continuously spawns a fresh army of 1/1 green Snake creature tokens with deathtouch every time a counter finds a home.