The Onga Wonga's Saxophone

When you use The Onga Wonga's Saxophone, a magical golden Saxophone appears in your hands(or floats in your mouth if you do not have hands), the target takes 17d20 necrotic damage and suffers effects of Unending Diarrhea*. If target is immune or resistant necrotic damage they take 17d10 radiance damage instead.

If you use any spell slot add 7d6 damage(from appropriate damage type; N or R) and cast random effects from Wild Magic Table for each level used.   

*Unending Diarrhea gives target 17d8 poison damage until they have 17 short rests or 37 long rests.