Cupid

From PhallaWiki

A Cupid is a role that possesses a once-per-game ability, usually triggered during Day 1. The role in question chooses two individuals, and masons then together. The two people in question may be converted to one of the involved party's win condition if the two people targeted had differing Conditions. The two targets may also die if the other target is killed in any manner.

This has the potential to change the game before it starts, especially if a mafia member is targeted. A Village Idiot practically prays to be targeted by a Cupid.

An example of a Cupid in action can be found in AdventFalls' Transylvanian Madness mini.