Boink (Bounceback)

When a hostile force bears down on you, entering a square within 10 feet of you that you can see, with a clap of your hands you create a large (5' diamater) ball of flexible rubber and hurl it in the assailants direction. The target must make a Constitution saving throw, or be pushed 10 feet backwards and knocked prone, ending their movement as the wind is knocked out comically with a resounding "BOINK" sound effect. If the target in question is armed with a weapon or a natural weapon that deals slashing or piercing, they have advantage on the saving throw. If a target armed with a slashing or piercing weapon succeeds their saving throw against this spell, they pop the rubber ball, preventing you from casting this spell again for 1d4 minutes.