First Appearance: Hvs.tCF 16
Binding arbitration is a spell produced by a Carnymancy Turnamancy caster link. The spell places the minds of the casters and target into a 2D fighting game. They proceed to attempt to exhaust one another's will power in simulated combat, even as they negotiate terms. The ultimate aim of the spell is to use "strongarm negotiation" on natural allies, coercing them into acting against their own best interests. The spell has very limited range and must be casted up close.
Real World References
The name of the spell is a reference to arbitration, in which two parties resolve a dispute and make a legally binding agreement out of court with the aid of a 3rd party.
The fighting game it places them in is a reference to Street Fighter.
Charlie's words and the fact that this spell is casted in the middle of a rapidly losing battle suggest that this spell is a "free action", meaning that the time spent in the fighting game will not pass any time in the "real" world.