"Magic 2013", +"can't attack", +!defender, +!detain, +!"you may change" (6)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Harbor Serpent can't attack unless there are five or more Islands on the battlefield.
Mogg Flunkies can't attack or block alone.
Enchant creature
Enchanted creature can't attack or block.
Flying
Slumbering Dragon can't attack or block unless it has five or more +1/+1 counters on it.
Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Slumbering Dragon.
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.
War Falcon can't attack unless you control a Knight or a Soldier.
Gatherer works better in the Companion app!