perplex

(verb) be a mystery or bewildering to. Synonyms: vex, stick, get, puzzle, mystify, baffle, beat, pose, bewilder, flummox, stupefy, nonplus, gravel, amaze, dumbfound. Examples: "This beats me!." "Got me--i don't know the answer!." "A vexing problem." "This question really stuck me."

(verb) make more complicated. Synonyms: complicate. Examples: "There was a new development that complicated the matter."