Lili, Wavebreaker Thief

Instant and sorcery spells you control have
cipher. (You may exile that 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.)
Commander dash {u/b} (You may cast this spell for its
dash cost. If you do, it gains haste, and it's returned
from the battlefield to its owner's hand or command
zone at the beginning of the next end step.)