Owl, Dimir Saboteur

Owl, Dimir Saboteur is unblockable
Whenever you cast an instant or sorcery with converted mana cost 3 or less, it gains cipher and
is encoded onto Owl, Dimir Saboteur.
(Then you may exile this spell card encoded on a creature you control. Whenever that creature
deals combat damage to a player, its controller
may cast a copy of the encoded card without
paying its mana cost.)