Lord Stavros assigns players to dance in pairs for 7 sec. While farther than 8 yards from your partner Lord Stavros punishes you, inflicting 4.5 Shadow damage every 0.5 sec sec.
In addition, Lord Stavros encourages your dance moves by marking each partner's location every 0.5 sec sec, causing it to erupt inflicting 40 Shadow damage to all players within 2.5 yards of the impact.