Katabatic Winds

Oracle Text

Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)

Creatures with flying can't attack or block, and their activated abilities with T in their costs can't be activated.

Card Rulings

6/8/2016 Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.