Ahab's Harpoon

This javelin has several hooks on its tip, turning it into an even deadlier weapon. Its shaft is strewn with several small corals of white and blue color.
This weapon is treated as magical for purposes of overcoming resistance to non-magical weapons.

Whaler's Haul: Before you make a ranged attack with this javelin, you can choose to take a -5 penalty to the attack roll. If the attack hits, the harpoon pierces the creature's skin and impales it. While impaled, the creature can use its action or bonus to pull the javelin out and take 1d6 piercing damage.
If you attacked an object or ground instead of a creature, the harpoon becomes anchored.
You can forego one of your attacks during your turn or use your reaction at the end of the round to magically pull out your harpoons from impaled creatures, attempting to pull the impaled creatures (you also pull all the harpoons you wish that are anchored to the ground by non-magical means). All impaled creatures must make a DC 16 Strength saving throw, they have a bonus or penalty to the saving throw equal to two times the number of categories they are above or below Medium size (for example, a Huge creature has a +4 bonus, while a Small creature has a -2 penalty). Additionally, the creature has a -2 penalty for each harpoon impaling it beyond the first pulled out simultaneously.
If the creature fails the saving throw, you can choose to pull it towards you 10 feet, knock it prone, or both, Additionally you can pull the creature up to an additional number of feet equal to 10 times the number of  harpoons pulled beyond the first. Whether the saving throw succeeds or fails, the creature takes 1d6 piercing damage per harpoon pulled.
When you use this feature, all the pulled javelins return to the container you drew them out of.

Reel In: As a bonus action, you can pull yourself towards a harpoon anchored to an object or ground that can sustain your weight. You travel at a speed of 100 feet per round and do not take falling damage, additionally, you do not provoke opportunity attacks during this movement. When the movement ends, the harpoon is no longer anchored and returns to the container you drew it from.

Proficiency with a Javelin allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, Damage, Thrown, Slow