GableStage director Joseph Adler has a knack for spotting talent before anybody else and then casting that talent in roles that seem both introductory and definitive. For evidence, look at Betsy Graver (Blasted and Farragut North), Ryan Didato (Red), and this year's Best Actress winner, Natalia Coego (Bad Jews). Arielle Hoffman continued this tradition with her stunningly acrid, marvelously lived-in performance as Ellie, the 17-year-old estranged daughter of a morbidly obese English professor in The Whale. Hoffman more than held her own with Gregg Weiner, one of the heavyweights — literally, in this case — of South Florida theater, playing off his character's 11th-hour bonding overtures with a kind of pitiless contempt that must have been challenging to summon. She embodied the modern jaded teenager with brutal authenticity, right down to her gestures, gait, and posture. And when Weiner finally pierced her armor of long-simmering anger and condescension, it was understated and beautiful, one of the most moving theatrical moments of the past year.