Elemental katana

A blade of the chosen element erupts from the hilt. The sword deals 1d8(1d10) elemental dmg, and the target must make a (CON) saving throw DC15 or suffer the corresponding effect.
Fire: The target is lit on fire.
Ice: The target's speed is reduced by 10.
Lightning: The target is stunned until the start of your next turn.
Water: The target is pushed back 10 ft.
Earth: Add 1d6 bludgeoning dmg.