Fangs of the Searing Serpent (Patreon)

Weapon (trident), very rare (requires attunement)

This bident was once entirely brass, but has become corroded and green over time. You have resistance to acid damage while attuned to this magic weapon. A target hit with this weapon takes an extra 1d6 acid damage from the attack; on a 6, the target must also succeed on a DC 16 Constitution saving throw or be poisoned until the start of your next turn.

Burning Venom. While holding the corroded bident, you can use an action to thrust it forward and speak its command word, causing it to spew a spiraling line of fire from its prongs. The line is 5 feet wide and 30 feet long. Each creature within that line must succeed on a DC 16 Dexterity saving throw or take 4d6 fire damage. The corrosion then flakes away from the weapon's surface like snakeskin, leaving it shimmering and brass, and its prongs remain wreathed in flame. For the duration, the weapon deals an extra 2d6 fire damage to any target it hits, instead of its acid damage, and it sheds bright light in a 20-foot radius and dim light for an additional 20 feet. The effect lasts for 1 minute or until you end it early using an action, at which point the corrosion reappears. This property can only be used if the weapon is covered in corrosion.

My bite will unleash a fire in your veins and scorch the earth. You will crumble under my burning radiance.