Kai, Sage of Dragons

At the beginning of your end step exile a dragon creature card from your hand, create a blue illusion creature token that is a copy of that card with
"When this card becomes the target of a spell or ability sacrifice it"
and "At the beginning of your upkeep sacrifice this creature and return the exiled card to the battlefield under its owner's control, it gains haste"
- If the sky could dream, it would dream of dragons