Electric Eel

Every hit leaves a charge on the target, and charged enemies zap each other once a second. The damage per tick climbs with the number of charged bodies in range and caps once a small group is tagged, so the correct way to use it is to sweep across everything in front of you rather than focus one enemy down.

The mark is filed as a whip debuff, and the game treats those separately from ordinary debuffs. Enemies that shrug off everything else, the giant mechanical worm being the obvious case, still take the full chain damage. Tag a stretch of segments and they feed each other. Pull this before the mechanical bosses and that fight becomes a formality.

The tag effects are strong enough that minions which fire fast and hit weak get the most out of it. Blade Staff is the usual pick, and the Queen Spider Staff gains an unusually large amount as well.