Andrex, Epical Genius

Hexproof
Brainstorm {1}: Create pixel artifact token.
When your opponent has less than 15 health, you may activate this card.
Activate {1}: Sacrifice five pixel tokens, all creatures under your control gain hexproof and Andrex, Epical Genius gains +2/+0 until end of turn.
When this creature attacks, you enemy gains a poison counter for each instant in their hand.
Ingenious!
-Jace