Wow is this a “fixed” [[Memory Jar]] in red? Memory Jar says until “the beginning of the next end step” which lets you time it for yourself, this one seems to always give the opponent a turn with the cards too. If you crack it on your opponent’s turn then they get to play at sorcery speed and you wouldn’t, and if you crack it on your turn then both players get to play their cards during a full turn.

Curves nicely into [[Oblivion Sower]]