Enchant creature
At the beginning of your upkeep, sacrifice Serra Bestiary unless you pay {W}{W}.
Enchanted creature can't attack or block, and its activated abilities with {T} in their costs can't be activated.
Activated abilities contain a colon. They’re generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.
Does prevent the use of activated mana abilities with {T} in the cost.