Detonation Dart

Damage. 1d4+1 Piercing Range. 20/60
Heatseaking. You gain a +1 bonus to attack rolls you make with this weapon. This bonus is doubled against creatures that are not Oozes, Plants or Undead.
Detonate. When you successfully hit a target with this dart, the dart explodes in a blaze of fire. The target and all creatures within 15ft. have to make a Dexterity saving throw (DC 15). The target you hit with the dart makes this saving throw with disadvantage. On a failed save they take 5d8 Fire damage and are stunned until the end of their next turn. On a successful save they only take half damage and are not stunned. The dart itself is destroyed in the process.