ViviVivi adds an amount of mana equal to his power, but only once on each of your turns
This set does have a lot of dragons, and that may keep him in check a little bit, but he still seems quite good to me
What's great about this planeswalker commander is there are all sorts of avenues to go down, you've got trample and haste being relevant keywords you want on most of your creatures, burn damage providing a win con if you can make Boo (or your other creatures) big enough, and a renewable token that makes a great target for sacrifice effects
Fate Unraveler, Underworld Dreams, Razorkin Needlehead, and Kederekt Parasite are all very similar, and theyre often seen in the same decks together
A powerful, synergy-driven deck built around Imotis cascade mechanic and big creatures