Again, the mechanical conceits of discarding as a cost and of tapping numerous creatures are naturally exploitable in Zombie decks
There's quite a few ways to do this, with one of the absolute best being Vigor: not only does it prevent Polukranos from taking damage, it actually adds +1/+1 counters whenever it would take damage
This version of Tribal Tribal focuses on powerful tap abilities such as: generating tons of mana off cards like Harabaz Druid and Manaweft Sliver drawing tons of cards off Sea Gate Loremaster getting rid of permanents with Devout Chaplain and Galecaster Colossus stealing stuff with Captivating Vampire and Gilt-Leaf Archdruid tutoring for what we need with Magda, Brazen Outlaw and Lin Sivvi, Defiant Hero We also run various ways to untap all our creatures to get even more value out of these tap abilities with Myr Galvanizer, Seedborn Muse, and Merrow Commerce
Armillary Sphere costs two, sacrifices for two with a tap, and then you can tutor up two basics and toss them into your hand
only an Amethyst/Steel card can be used
The artwork here is from the Mirrodin set and shows a woman holding out a scepter and focusing intently as a large wave of energy pulses from it