Myna, Shieldslinger

When Myna enters the battlefield, create a
colorless Equipment artifact token named Shield
with "Equipped creature gets +0/+2 and has
hexproof" and equip {2}. Attach it to Myna.
Unattach an equipment with mana value X,{x}: Deal X plus 2 damage to any target.
The first time each turn you would activate an
Equip ability that targets Myna, it costs {2} less to activate.