Bottled Will-o'-Wisp (Patreon)

Wondrous item, uncommon

This small bottle carries a will-o'-wisp inside it, as well as a trinket from its previous life. The wisp is magically tethered to the trinket as long as it stays within the bottle, keeping the wisp bound to the bottle and incapable of escape on its own.

While holding the bottle, you can use a bonus action to shake it, causing the wisp to glow brighter. The shaken wisp sheds bright light in a 10-foot radius and dim light for an additional 10 feet for up to 1 hour or until you end the effect early (no action required).

Alternatively, you can use an action to unstopper the bottle and unleash the wisp in a direction of your choice. The wisp then flies out at a target that you can see within 30 feet of you. Make a ranged spell attack for the wisp, using an attack bonus of +5. On a hit, the target takes 3d8 lightning damage. Hit or miss, the wisp immediately returns to the trinket in the bottle, which you then reseal.

If the wisp's attack roll misses the target by 5 or more, there is a 50 percent chance that the wisp breaks its tether to the trinket and doesn't return. When that happens, the wisp becomes hostile to you and your allies. If you're holding the empty bottle, you can use an action to make a Dexterity (Sleight of Hand) check contested by a will-o'-wisp's Dexterity (Acrobatics) check, provided that the wisp is within your reach. On a success, the wisp becomes trapped in the bottle, and a new trinket appears for it.

When a wisp becomes untethered from the trinket in the bottle or if the trinket is removed from it, the trinket immediately turns to ash.

"I told you shaking the bottle was a bad idea! You made the little guy mad!"

"Okay, well that 'little guy' just nearly electrocuted Dr. Winslow. Help me catch it!"