Bacchanite

Bacchanites were a parasitic species that fed on the pain and sorrow of others. One of them disguised itself as a human and was a bartender in Vienna, giving customers tainted wine that made them have hallucinations of dead friends and family, then feeding on their grief. The Eighth Doctor stopped it, freeing Johann Wolfgang von Goethe and others from its influence. (PROSE: The Sorrows of Vienna)