The Helis scroll is an item that immediately burns the enemy, although it can only affect undead mobs (e.g. mummies, skeletons, goops). It can be used an infinite of times, and is believed to do a percentage of the enemy's health, such 152 damage/second to the goomonger, but only around 2 to mummies, and 5-7 to skels. Its counterpart is the Poynu Scroll, which cannot affect undead mobs (skels, goops, mummies).
TIP: Use this with the tomb keeper boss; He takes HIGH damage from this!