Getting what you wished for often doesn’t turn out well in real life. But it never turns out well in horror films, as the new movie from Curry Barker vividly demonstrates. Trafficking a well-worn theme — the classic short story “The Monkey’s Paw,” the exemplar of the concept, dates all the way back to 1902 — Obsession makes it fresh and original with its superbly orchestrated blending of dread, jump scares and dark comedy. The film represents an instant breakout for its director-screenwriter, who first received attention with his YouTube comedy sketches created in collaboration with Cooper Tomlinson (one of this film’s supporting players) and his extremely low-budget horror film Milk & Serial . It’s another example of how the horror genre has become a launching pad for ambitious filmmakers. The central characters are Bear (Michael Johnston, MTV’s Teen Wolf ), a dweebish employee at a musical instruments score, and his co-worker Nikki (Inde Navarrette, Trap House ), on whom he has a helpless crush.…