Xathrid Gorgon
Creature — Gorgon
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
, 
: Put a petrification counter on target creature. It gains defender and becomes a colorless artifact in addition to its other types. Its activated abilities can't be activated. (A creature with defender can't attack.)
Wesley Burt
Magic 2013 Promos (PM13)
• #118★Rulings
Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.
(wotc • 2016-06-08)
The effects of Xathrid Gorgon’s ability don’t depend on the petrification counter. If that counter is removed, the creature remains a colorless artifact with defender, and so on.
(wotc • 2012-07-01)
Rulings
Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.
(wotc • 2016-06-08)
The effects of Xathrid Gorgon’s ability don’t depend on the petrification counter. If that counter is removed, the creature remains a colorless artifact with defender, and so on.
(wotc • 2012-07-01)