Flurrycast

Split second (As long as this spell is on the
stack, players can't cast spells or activate
abilities that aren't mana abilities.)
This spell costs {1}{r} less to cast if it targets
a spell or ability you control.
You may choose new targets for target spell
or ability, then it gains split second.
Artwork source:
https://www.artstation.com/artwork/oOe9E4