Hashishene? Yes, it's a Real Terpene

This is a very unique terpene that is rarely found in cannabis flower, but always found in Moroccan style hash. Hashishene, or hashinene is a by-product of the unique and very simple hash production process used in Northern Africa, specifically the Rif Valley of Morocco. 

Hashishene's full chemical name is 5,5-dimethyl-1-vinylbicyclo[2.1.1]hexane and was first isolated in 2014. Studies found that hashishene is actually an oxidative product of the terpene Myrcene that is the result of drying and curing a harvest on rooftops in the equatorial sun, as the Moroccans have done for many centuries. The heat and UV light catalyze the transformation. Hashishene has the same molecular formula as Myrcene, but with a "radically different" chemical structure.

This happens with other terpenes, too. Most of the "secondary" terpenes in cannabis are actually just oxidative products (analogs) of the top 8 terpenes found in cannabis, including Myrcene, Pinene, Humulene, and Caryophyllene.

There is little research about possible medical benefits, but those who have experienced it say it's a different effect than Myrcene. There is also some CBD as well as Hashishene in most dark Moroccan hash. 

This article from High Times covers it in some detail.