Since its reveal, people have been trying to find ways to adequately break the giant cactus monster, and many have succeeded
The best way to utilize this planeswalker is to: Play Jace, Mirror Mage Pay the kicker price (2 mana) Create a copy of Jace, Mirror Mage with 1 loyalty counter Activate the first ability on the copy to scry and determine the next card draw Activate the second ability on the original Jace, Mirror Mage to draw a card and keep both planeswalkers in play You can repeat this pattern each turn, intertwining the roles of both Jace planeswalkers
You might also want to include as many orcs and goblins as you can for sacrifice fodder
If the mana ability of that permanent puts any restrictions or riders on the mana it produces, that will apply to all the mana it produces this way
This creature enters tapped if it's not your turn
Fetch Sphinx of the Guildpact from your Karnboard