For 4 of your turns the serpent bites its tail: your rooks' and queen's horizontal moves wrap around the board edge.
You draft World Serpent in Buff mode. Passive: it works on its own the whole time you hold it, with nothing to activate.
As a movement card, it changes how one of your pieces is allowed to move.
“The board was never flat. You just moved like it was.”
Affects your rooks and queens.