Amass Oozes X, where X is the number of creature types among creatures on the battlefield. Don't count changelings. That would be ridiculous. (To amass Oozes X, put X +1/+1 counters on an Army you control. It's also an Ooze. If you don't control an Army, create a 0/0 black Ooze Army creature token first.)
Legalities
tlrnot legal
duelnot legal
brawlnot legal
pennynot legal
PreDHnot legal
futurenot legal
legacynot legal
modernnot legal
paupernot legal
alchemynot legal
pioneernot legal
vintagenot legal
historicnot legal
standardnot legal
Timelessnot legal
commandernot legal
Gladiatornot legal
Old Schoolnot legal
Premodernnot legal
Oathbreakernot legal
Standard Brawlnot legal
Pauper Commandernot legal
Context
Across the 1 printing of this card, the trailing-90-day price band runs from $7.00 to $7.00 across 36 observations. Headline volatility across the concept reads stable.
Card type: Sorcery. Color identity: green. Mana cost: {3}{G} (4 converted).