Dimir Keyrune
Artifact
: Add 
or 
.
: This artifact becomes a 2/2 blue and black Horror artifact creature until end of turn and can't be blocked this turn.
A key that slips through every lock.
Daniel Ljunggren
Rulings
Activating the ability that turns the Keyrune into a creature while it's already a creature will override any effects that set its power and/or toughness to another number, but effects that modify power and/or toughness without directly setting them will still apply.
(wotc • 2013-04-15)
Until the ability that turns the Keyrune into a creature resolves, the Keyrune is colorless.
(wotc • 2013-04-15)
Rulings
Activating the ability that turns the Keyrune into a creature while it's already a creature will override any effects that set its power and/or toughness to another number, but effects that modify power and/or toughness without directly setting them will still apply.
(wotc • 2013-04-15)
Until the ability that turns the Keyrune into a creature resolves, the Keyrune is colorless.
(wotc • 2013-04-15)