At the beginning of your end step, put a loyalty counter on another target planeswalker you control.
[+1]: Create a 1/1 red Wizard creature token with "T: Add R. Spend this mana only to cast a planeswalker spell."
[-3]: You draw X cards and Commodore Guff deals X damage to each opponent, where X is the number of planeswalkers you control.
Commodore Guff can be your commander.

NOTE: Stock image, not actual card.