Halaster's shaking hand

Halaster's shaking hand was a evocation spell that functioned exactly like Bigby's interposing hand, except that the hand was capable of grappling or otherwise wrestling with the effects of Bigby's hand spells that have been evoked. When two of these arcane hands wrestled with one another, it resembled a large disembodied handshake.

The spell was developed by the powerful archmage that dwelled within the Undermountain, Halaster Blackcloak.