Urza's Incubator
Artifact
As this artifact enters, choose a creature type.
Creature spells of the chosen type cost 
less to cast.
"Stop thinking like an artificer, Urza, and start thinking like a father!" —Rayne, chancellor of the Tolarian Academy
Pete Venters
The List (PLST)
• #C15-273Rulings
You choose a creature type right as it enters, before any continuous effects are applied or trigged abilities trigger.
(wotc • 2004-10-04)
Multiple Incubators are cumulative.
(wotc • 2004-10-04)
Rulings
You choose a creature type right as it enters, before any continuous effects are applied or trigged abilities trigger.
(wotc • 2004-10-04)
Multiple Incubators are cumulative.
(wotc • 2004-10-04)