Oppressive Rays
Enchantment — Aura
Enchant creature
Enchanted creature can't attack or block unless its controller pays 
.
Activated abilities of enchanted creature cost more to activate.
Mark Zug
Journey into Nyx (JOU)
• #19Rulings
Activated abilities are written in the form “Cost: Effect.” Some keywords are activated abilities and will have colons in their reminder texts. Static and triggered abilities are unaffected by Oppressive Rays.
(wotc • 2014-07-18)
The enchanted creature's controller can choose to not attack or block with it even if it must attack or block if able. Players can't be forced to pay a cost to attack or block.
(wotc • 2014-07-18)
Rulings
Activated abilities are written in the form “Cost: Effect.” Some keywords are activated abilities and will have colons in their reminder texts. Static and triggered abilities are unaffected by Oppressive Rays.
(wotc • 2014-07-18)
The enchanted creature's controller can choose to not attack or block with it even if it must attack or block if able. Players can't be forced to pay a cost to attack or block.
(wotc • 2014-07-18)