When Lord of Tresserhorn enters the battlefield, you lose 2 life, you sacrifice two creatures, and target opponent draws two cards.
: Regenerate Lord of Tresserhorn.
10/4/2004 When Lord of Tresserhorn enters the battlefield, if you have zero or one other creature on the battlefield, Lord of Tresserhorn itself will be sacrificed as part of its ability’s effect. Regeneration won’t save it. The rest of the effect still happens.
10/4/2004 Since this is a loss of life and not a payment, your life total can be reduced below zero by this.