Modern Horizons 2 is designed for the Modern format, which lets you play with cards from all the way back to 2003, meaning the power-level is through the roof
It can minus once when it enters, but not two turns in a row
Even go-wide token decks can run selective board wipes like Hour of Reckoning
A member of the former Commander rules committee dubbed them legal, but only for the person whose name is on the card - meaning that, as soon as they're sold, they go from functional playing pieces to pure collector's items
It must contain 60 cards, up to two Ink types, and no more than four of the same card
When it comes into play, all creatures in play get -X/-X for the turn, with the X equaling what you put into the casting cost