The multi-person rainbow costume has another element to it.
As well as those playing the rainbow, there must be another who dresses as The Viking. The Viking has the power, at any point during the party, to scream at the top of her/his voice “RAINBOW ASSEMBLE!” The rainbow parts must then rush together from across the room, the toilet, the bar or wherever they may be and gather around The Viking. They then must say their colour, loud & proud, for the whole room to hear whilst placing their right hand upon the Vikings head. One all colours have been called out and hands placed everyone, including the Viking must roar “RAINBOW!” The final act is The Viking thrusting her/his sword/hammer into the air with a look of fearlessness or his/her face. And then back to drinking.