Teneb, the Harvester
Legendary Creature — Dragon
Flying
Whenever Teneb deals combat damage to a player, you may pay 
. If you do, put target creature card from a graveyard onto the battlefield under your control.
Zoltan Boros & Gabor Szikszai
Planar Chaos (PLC)
• #163Rulings
You choose the target when the ability is put on the stack, and you choose whether to pay when it resolves.
(wotc • 2007-02-01)
Rulings
You choose the target when the ability is put on the stack, and you choose whether to pay when it resolves.
(wotc • 2007-02-01)