Blast Javelin

Weapon (javelin), uncommon

This javelin radiates heat from within when thrown. When you make a ranged attack with this magic weapon and speak its command word, it becomes primed to detonate. If the target is a creature and the attack hits, the javelin immediately explodes; on a miss, the javelin instead lands at a random point beyond the target within 30 feet of it. If the attack misses, or if the target isn't a creature (such as if you threw it at a point or an object), the javelin instead explodes at its location at the start of your next turn. If a creature moves the javelin before then, it explodes early.

When the javelin explodes, each creature within 20 feet of it must make a DC 13 Dexterity saving throw; the original target of the attack makes the saving throw with disadvantage. A creature takes 3d6 fire damage on a failed save, or half as much damage on a successful one.

Once the command word has been used, it can't be used again for 1 minute. After that time, it shouldn't be used again until the next dawn: each time it's used again before then, the javelin has a 50 percent chance to destroy itself when it explodes.

Amaranth slid to a stop and slammed a shimmering red javelin into a wood beam before sprinting the last corridor to the gardens.

A dozen footsteps clattered behind her, but stopped short with the sound of an explosion and cries of pain. They'd be fine—the guards' scales were nearly a match for her own rosy ones—but it gave her the breathing room to keep running in obscurity. After all, they couldn't learn that it was their own princess that had robbed the vault.

Checking her bag, she counted two more javelins: dimmed and charred. She grabbed them in either hand and hurled them, stepped, into the wall. In one smooth motion, she leapt from one javelin to another as springboards to clear the high wall, landing softly on its ramparts as the path behind her detonated. She heard the splintering of at least one of them in the blast.

She allowed herself a smug smile for the dramatic exit.