Increases damage to "arthropod" mobs (spiders, cave spiders, silverfish and endermites)
Each level separately adds 2.5 (Half Heart.svg × 2 1/2) extra damage to each hit, to "arthropods" only. The enchantment will also cause "arthropods" to have the Slowness IV effect when hit. The duration of the effect is a random value between 1 and 1.5 seconds at level I, increasing the max duration by 0.5 seconds each level, up to 3.5s with Bane of Arthropods V.
Notably, the slowness effect applies not only to "arthropod" kills with the sword itself, but to any "arthropod" kills while simply holding the sword.