The Jolly Balloon Man would work wonders in this deck, since it can contribute to Arabella in a lot of ways like if it copies Siege-Gang Lieutenant, for example
When you combine these with ways to exile cards to play in later turns, and the sheer force of constantly attacking, you can end up with a deck thats simply faster than most decks can deal with
The 6-mana version is also good, of course, but its the secondary mode of the card
The deck adds a number of powerful ramp spells to help you cast Slivers ahead of curve as well as potent removal effects to keep your opponents' most powerful threats at bay
While the precon is a good baseline, you might wonder, How do I dial it up to 11? Youre in luck
Karn's Bastion is a great utility land for infect decks since it can proliferate at instant speed and is more difficult to remove than one of your proliferating artifacts