Necrosynthesis

Enchantment — Aura

Enchant creature

Enchanted creature has "Whenever another creature dies (is put into the graveyard from the battlefield, tokens are put into the graveyard before ceasing to exist), put a +1/+1 counter on this creature."

When enchanted creature dies, look at the top X cards of your library, where X is its power. Put one of those cards into your hand and the rest on the bottom of your library in a random order.

Legality

Format	Legality
1v1 Commander	Legal
Alchemy	Legal
Archenemy	Legal
Arena	Legal
Block Constructed	Legal
Brawl	Legal
Canadian Highlander	Legal
Casual	Legal
Commander / EDH	Legal
Commander: Rule 0	Legal
Custom	Legal
Duel Commander	Legal
Gladiator	Legal
Highlander	Legal
Historic	Legal
Legacy	Legal
Leviathan	Legal
Limited	Legal
Modern	Legal
Oathbreaker	Legal
Pioneer	Legal
Planechase	Legal
Pre-release	Legal
Quest Magic	Legal
Standard	Legal
Tiny Leaders	Legal
Vanguard	Legal
Vintage	Legal