Flame Tongue Javelin

While holding this magic weapon, you can take a Bonus Action and use a command word to cause flames to engulf the damage-dealing part of the weapon. These flames shed Bright Light in a 40-foot radius and Dim Light for an additional 40 feet. While the weapon is ablaze, it deals an extra 2d6 Fire damage on a hit. The flames last until you take a Bonus Action to issue the command again or until you drop, stow, or sheathe the weapon.

Slow (Mastery): If you hit a creature with this weapon and deal damage to it, you can reduce its Speed by 10 feet until the start of your next turn. If the creature is hit more than once by weapons that have this property, the Speed reduction doesn't exceed 10 feet.

Thrown: If a weapon has the Thrown property, you can throw the weapon to make a ranged attack, and you can draw that weapon as part of the attack. If the weapon is a Melee weapon, use the same ability modifier for the attack and damage rolls that you use for a melee attack with that weapon.

Proficiency: simple, javelin Source: Dungeon Master's Guide (2024) p. 263