There is a legal phrase called promissory estoppel, which essentially means that if your promise has serious repercussions for the other party and by not keeping it you caused some sort of harm (financial, in this casespoiler alert), youre liable for that harm and can be prosecuted
Related While some cards hold serious power in the game still, like the Moxen, a lot of outdated cards are still limited from printing
After New Phyrexia's defeat, the remaining Simic discovered that, out of all the creatures they experimented on, only a few had survived untainted by compleation
These Leaders are so powerful theyve been banned
Ashnods Altar, Altar of Dementia, and the Eldrazi Monument give us three options for sacrificing creatures
It doesn't target any player, even if the spell mastery ability applies