mtg parley cards Boneyard [94] [Ixalan] [Foil] – Face to Face Games Exile up to five target creature cards from graveyards Selva, Explorer Returned Card |

This means that you can expect Draft decks to be slightly better, more powerful, faster, and (most importantly) more focused than in Sealed Deck

However, if even a single card falls off your head, you have to exile all of the cards and sacrifice this enchantment

You gain life equal to that creature's power

In short, this card forces players to play another game of Magic using their libraries as decks

Worse, the flavor text seems to hint at the Disruptive Student actually being Teferi (most players read it that way, at least)

For example, if it blocks a 12/12 creature with trample, that creature's controller must assign at least 8 of that creature's combat damage to Diamond Weapon, and the remainder can be assigned to the defending player, planeswalker, or battle