Precursor's Sacred Pool

Precursor's Sacred Pool enters play, each
opponent draws two a card.
{t}:Add {u}.
When a player has 7 or more cards in their
hand, transform Precursor Cenote Font
into Autochonian Spirit Scroll.
"Any cenote is a holy place to the Aztoken, a source
of vital fresh water. One hosts a monument ancient
beyond all memory; even their wisest can only guess.