Necrosynthesis

Enchant creature
Enchanted creature has "Whenever another creature dies, 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.

Withering Boon

As an additional cost to cast this spell, pay 3 life.
Counter target creature spell.

Unspeakable Symbol

Pay 3 life: Put a +1/+1 counter on target creature.