Infiltrator. Any creature that takes lightning damage from your Lightning Launcher glimmers with magical light until the start of your next turn. The glimmering creature sheds dim light in a 5-foot radius, and it has disadvantage on attack rolls against you, as the light jolts it if it attacks you. In addition, the next attack roll against it has advantage, and if that attack hits, the target takes an extra 1d6 lightning damage.
It seems like the intent was that with Extra Attack, you will consume your first attack, and only your second attack will be viable to apply this effect if you hit first. However, through haste, Action Surge, etc., if you are to gain another attack, would you be able to chain this twice in your turn? That is, assuming you hit would you:
- Apply effect via hit.
- Roll second attack with advantage and deal an extra 1d6.
- Repeat step 2 with a third attack.
- The effect is again applied, leaving others to benefit from the advantage and extra 1d6 damage again after your turn.