Spell engine Spell engine was an arcane abjuration or alteration spell that created a magical device that absorbed virtually all spells cast in the surrounding area and produced a light that was conducive to magical study . Effects . There were at least three slightly different versions of this spell . The newer version was wholly in the abjuration school while the older versions belonged to both the abjuration and alteration schools . This spell took a full ten minutes to cast and produced an invisible and intangible disk : the spell engine . The older versions placed the 12 ft ( 3 . 7 m ) diameter disk at the point where the caster stood at the time of casting , while the newer version produced a 10 ft ( 3 . 0 m ) diameter disk that could be placed up to 65 ft ( 20 m ) away ( even farther for more experienced casters ) . For all versions , the disk was 2 ft ( 60 cm ) thick . The effect was permanent until dispelled or destroyed . Before the spell engine was activated , its presence could be detected by " detect magic " or " detect invisible " spells ( if cast outside the spell engine ' s area of effect ) or by the equivalent natural abilities . Once activated , the disk became visible but remained insubstantial . With few exceptions , any divine or arcane spell , any spell - like ability , or any magic item discharged within the area of effect would activate the spell engine and be absorbed , as if by a " rod of absorption " with unlimited capacity , causing the disk to turn and give off a white glowing light . All further magical casting in the area was prevented from having its desired effect as the energies were siphoned into the spinning disk instead . Magical effects such as a " magic mouth " or a " glyph of warding " that were in existence before the casting of " spell engine " were not absorbed and continued to operate under the protection of the spell engine . The older versions of " spell engine " protected a spherical volume with a radius of 10 ft ( 3 . 0 m ) per level of the caster , ignored barriers such as walls and solid objects , and the disk spun faster and glowed brighter with each absorbed spell . The oldest version also gave off a gentle susurration like rushing water . The newer version covered only the physical dimensions of the disk itself , spun at a constant rate , and glowed like a silent torch . The glow given off by the spinning disk was beneficial to spellcasters . Studying or praying in the light of the spell engine allowed them to memorize spells in half the normal time . The amount of rest needed to recover was not affected , only the time to prepare spells . The spell engine could be destroyed by a " disintegrate " spell , causing a massive explosion of force . The same thing happened if a magic item came in contact with the glowing disk . Potion s and scroll s were not enough to trigger the destruction of the spell engine , but contact with other magic items and artifact s would cause detonation . An artifact and anyone wielding it were shifted to another plane of existence , but magic items of lesser stature were destroyed . The only known method to safely remove an active spell engine was to use a properly worded " limited wish " , " wish " , or " alter reality " spell . Components . In addition to verbal and somatic components , this spell required some material components to cast . The newer version took a small disk made of bone , one of the caster ' s tears , and a silver wheel worth at least 1 , 000 gp . The older versions used a disk of bone , ivory , shell , or polished marble , a tear from the caster , and a cut gem stone worth at least 1 , 000 gp . History . This spell was added to a spellbook owned by the famous mage and explorer Sabirine . It was inserted before the title page of her tome " Sabirine ' s Specular " and hidden with a " secret page " spell by an unknown agent . Sometime after it was discovered it was published in " Volo ' s Guide to All Things Magical " and became generally known , but it was rare to find it .