The first time you amass, you create a 0/0 Zombie Army token and put a number of +1/+1 counters on it equal to the number of amass
Unit Cards are placed on a field and will deal damage to the player in real-time
While its plenty powerful, its the effect on perceived barrier-to-entry that really posed a problem because casual players watching Commander games in passing could reasonably assume that they needed hundreds (now thousands) of dollars in Power-9 mana as table stakes, just to join the format
Chart shows the price of Hydreigon #10 at the end of each month going back as long as we have tracked the item.
Even so, theres probably an insufficient critical mass of payoffs and wincons for these strategies if they keep killing your Nekusar, for example
It's a bunch of sea creatures, with that one saw-shark and weedy seadragon being quite prominent