Shadowfax, Lord of Horses

Eminence — Each Horse, Unicorn and Pegasus
creature in your hand, library or on the
battlefield becomes a Horse, Unicorn, Pegasus
creature in addition to its other types, as long as
Shadowfax, Lord of Horses is in the command
zone or on the battlefield.
Whenever a Horse you control attacks, it gains
+X/+X, trample and lifelink. X equals the
amount of Horses that are attacking.