Chalice Vine

This is a Chalice Vine flower or Solandra grandiflora. Quoting from Wikipedia: Solandra:

Solandra /soʊˈlændrə/ is a genus of flowering plants in the nightshade family, Solanaceae. It is named after the Swedish naturalist Daniel C. Solander. 

The vines it contains are commonly known as chalice vines and are native to the Caribbean, Mexico and South America. They have very large flowers and glossy foliage. Also called Cup of Gold. 

Solandra grandiflora was once (and likely still is) used by the Huichol of Mexico and other tribes of the region where it is known by the name "kieli" or "kieri" with some archaeological evidence supporting the theory that its use as a hallucinogen predates that of "Peyote" (Lophophora williamsii). A tea from the branches and more so from the roots and fruits is used as an inebriant in native traditions. The alkaloids present include atropine, noratropine, hyoscyamine, and tropine with about 0.15% overall content in the leaves.

This is probably why nightshades are usually referred to a "deadly."