Dynameter

Chose a weapon that you are holding or carrying, you create continual explosions on the tip and edges of your weapon. A soft ticking sound emits from your weapon. When you cast this spell, on every one of your actions, you must make the attack action with you weapon. On your first attack you deal an extra 2d8 fire damage, second you have disadvantage on attacking and take 2d8+1d4 fire damage, on your 3rd 2d8+2d4, 4th disadvantage and you take 2d8+3d4 and so on. When there Is no one left to attack the spell ends and you take 1d4 fire damage