The Bittercup, or the Bitter Cup, is an artifact sacred to Clavicus Vile. The Cup was lost in ancient Chimeri ruins on an island in the Sheogorad region of Vvardenfell before it was recovered by the Nerevarine in 3E 427. It slowly fills itself with an unknown nectar that, when drunk, enhances one’s strengths while magnifying their weaknesses.
The Bittercup is an ornate cup made of an unknown material that fills itself with an unknown nectar. If a character drinks all of the Nectar contained within then they permanently increase their highest Characteristic by 3d8 and permanently reduce their lowest Characteristic by the same amount (to a minimum of zero).