Astral Cornucopia

The triple-X cost is the whole bet: every three mana you sink in buys one charge counter, and every charge counter becomes a mana of any one color, forever. That tax explains why it sees the most use at the high end, dropped for six or nine to leap a turn or two ahead. The catch is buried in the timing. Cast for X=1 it is a Manalith that cost three mana to do a two-mana job; cast for X=4 it is twelve mana up front for four mana per tap, a one-turn-per-loop investment that only pays off in decks already swimming in mana. It does not fix on entry the way Chromatic Lantern does: each activation locks you into a single color, so the counters that look like fixing are really a pile of same-color mana you commit to per tap. Where it earns its keep is as a proliferate target. The counters are not just storage; they are a value that wants to grow, and any effect that adds a charge counter turns a stalled rock into an escalating one. That interaction is the design's real axis: read as a standalone ramp piece it is overpriced, but read as a counter that happens to produce mana, it sits in a different category of card entirely.