The Binding of Fenrir

Enchant creature with power 4 or greater.
When The Binding of Fenrir enters the
battlefield, tap enchanted creature.
Enchanted creature cannot attack or block
and does not untap during its owner's
untap step.
"Rather than that you question my courage, let
someone put his hand in my mouth as a pledge that
this is done in good faith." - Poetic Edda