Hexerei
Bestimme eine Kreatur deiner Wahl, die du kontrollierst, und eine Kreatur deiner Wahl, die du nicht kontrollierst. Die Kreatur, die du kontrollierst, erhält +2/+1 bis zum Ende des Zuges, falls sie ein Ritter ist. Dann kämpfen die Kreaturen gegeneinander. (Jede der Kreaturen fügt der anderen Schadenspunkte in Höhe ihrer Stärke zu.)
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.
You can't cast Joust unless you choose both a creature you control and a creature you don't control as targets.
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.
If either target is an illegal target as Joust tries to resolve, neither creature will deal or be dealt damage.