Custom effect assistance requested

[SailorLovins]

I am trying to create an NPC that has a unique attack. I know how to make the base attack work with the NPC (Ranged Weapon Attack: +4 to hit, range 20/80 ft., Hit; 7 (2d6) fire damage.


This attack is a sticky fire and I is meant to accumulate 1d6 fire damage every time the attack is successful. Is it possible to create an effect that deals damage to the target at the start of its turn? How do I tell the NPC Action to even place an effect onto a target? Is it likely that the DM will have to track the amount of effects on the target and manually roll the damage at the start of the turn? If so how do I word the effect to be placed on the target so that it is all included in the ranged weapon attack?

[LordEntrails]

https://www.fantasygrounds.com/forum...ffects-on-NPCs

So try;
Ranged Weapon Attack: +4 to hit, range 20/80 ft., Hit; 7 (2d6) fire damage and the target takes 4(1d6) fire damage at the start of each of its turns.