Dukkha
From Tardis Wiki, the free Doctor Who reference
Dukkha was a manifestation of the Mara. He appeared to Tegan Jovanka in a dream. He tempted and tormented her with mind games and thought paradoxes until she agreed to a pact with him. The deal permitted the Mara to take her as a host, allowing it a physical presence in the real world. (TV: Kinda)
Behind the scenes
In Buddhism, one of the three marks of existence is dukkha which roughly translates to "suffering".
