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
Canadian Highlander	Legal
Casual	Legal
Commander / EDH	Legal
Commander: Rule 0	Legal
Custom	Legal
Duel Commander	Legal
Gladiator	Legal
Highlander	Legal
Historic	Legal
Historic Brawl	Legal
Legacy	Legal
Leviathan	Legal
Limited	Legal
Modern	Legal
Modern Beyond Horizons	Legal
Oathbreaker	Legal
Pioneer	Legal
Planar Constructed	Legal
Planechase	Legal
Pre-release	Legal
Quest Magic	Legal
Standard	Legal
Standard Brawl	Legal
Tiny Leaders	Legal
Vanguard	Legal
Vintage	Legal