Dot Dealer

The Damage Over Time (DoT) is a magical enchantment item used to imbue weapons or shields with a persistent damage effect. Each application of this scroll increases the inflicted damage over time (DoT) tick effect, compounding by 5% per enchantment, up to a maximum cap of +50 additional damage per tick

The Scroll can be crafted in the Enchanting section in Scroll crafting. It requires level 53 enchanting before you can craft it. You need 1 scroll, death,chaos, and blood runes. 80 of each, and 900 silver in order to craft. Time to craft varies depending on haste.

Trivia

Some scholars believe this scroll was originally developed by fire mages seeking to replicate the effects of their burning spells on weapons.