Complex sentence: Nightcrawler and Colossus destroy the generators for Alkali Lake, and he is plagued by visions of a youthful angry Jason Stryker, who keeps reminding him that he left him to die.
Split into simpler sentences: Nightcrawler and Colossus destroy the generators for Alkali Lake. Nightcrawler is then plagued by visions of a youthful, angry Jason Stryker, who continues to remind Nightcrawler that he left him to die.