Choose target creature you control and target creature you don't control. The creature you control gets +2/+1 until end of turn if it's a Knight. Then those creatures fight each other. (Each deals damage equal to its power to the other.)
"Life is a tournament that rewards the bold."
—Syr Layne, knight of Embereth
(04/10/2019)
If the creature you control is an illegal target as Joust tries to resolve, no creature gets +2/+1. If that creature is a legal target but the creature you don't control isn't, it still gets +2/+1 until end of turn if it's a Knight.
(04/10/2019)
The target creature you control gets +2/+1 only if it's a Knight as Joust resolves. It'll still fight if it doesn't get +2/+1.
(04/10/2019)
You can't cast Joust unless you choose both a creature you control and a creature you don't control as targets.
(04/10/2019)
If either target is an illegal target as Joust tries to resolve, neither creature will deal or be dealt damage.
