Petals of the Midnight Lotus.

Burning and inhaling the fumes of the Petals allows the person to see invisible and ethereal creatures and objects, burning this also grants casters a +10 to all arcana or religion checks, as well as lowering the casting time of ritual spells to half the time normally needed to cast the spell. 
The midnight lotus is not known to grow in any specific area's and its history is mostly unknown
Side effects for inhaling these fumes include: 1 wisdom damage until a long rest, Vivid, and terrifying hallucinations, involuntary astral projections which may include what looks like hallucinations but are in fact completely real and dangerous. The side effects for inhaling these fumes are stacking the more you inhale the worse the effects become.