Fire shroud

Fire shroud, originally named flame shroud and also published under the name shroud of flame,  was an arcane evocation spell that caused one creature to be engulfed in flames and endanger those around it. Post-Spellplague, this spell attacked all enemies close to the caster, but with less intensity. Colloquially, it was called the "trollkiller" spell.

Effects
The earliest versions of this spell could target a single creature up to 10 yd (9.1 m) away. A later version increased this range relative to the level of the caster. The post-Spellplague version was centered on the caster themselves, but attacked all enemies (and only enemies) within a radius of 15 ft (4.6 m).

Unless the target managed to resist the casting of this spell, it immediately started to burn. All flammable items worn or carried by the target also caught fire, although magical items had their own chance to resist the fire. Volatile oils were easily ignited by the flames and added their damage to the conflagration. In the pre-Spellplague versions, the immolation was so intense that flares were thrown off the target creature and could possibly burn or ignite other creatures or objects within 10 ft (3.1 m).

A protection from fire spell or a ring of fire protection prevented personal fire damage if employed against this spell, but did not prevent the flames or flairs from threatening other things they touched. All versions of this spell continued to burn their target(s) until the duration of the spell expired, or until a target doused the flames, or until it was dispelled, whichever occurred first.

Components
The pre-Spellplague versions required verbal and somatic components as well as a pinch of saltpeter, a small bit of phosphorous, and a sample of lace or spiderweb. The post-Spellplague version required only a slight gesture to cast.

History
This spell came to the attention of a mage, Ulthorn, in Waterdeep around the mid–11th century DR when a caravan master from the east named Muirhar brought him the Spellbook of Daimos, which contained flame shroud and other spells. This mysterious tome had been found on the body of a gnoll after the caravan survived an attack in Bleached Bones Pass. Ulthorn kept it secret for many years, revealing it only to his apprentice Rendergallis, and the book disappeared after Ulthorn's death.

The spell was slowly passed around to various wizards over the years, and some 300 years later it was published as shroud of flame in "Volo's Guide to All Things Magical" shortly after the Time of Troubles. It remained a rare spell, however.