What happens to Othello when Iago rouses his jealousy?
As Iago says, Othello becomes jealousy personified--the "Green-Eyed Monster."
O, beware, my lord, of jealousy;
It is the green-eyed monster which doth mock
The meat it feeds on; that cuckold lives in bliss
Who, certain of his fate, loves not his wronger;
But, O, what damned minutes tells he o'er
Who dotes, yet doubts, suspects, yet strongly loves!
As Emelia says, Othello becomes a stomach to churn and spit out women, who seem worthless status symbols to him:
Othello becomes a belching, seizure-ravaged, tongue-tied beast who plots double murder and suicide rather than suffer a stain on his manly reputation. Just listen to his monosyllabic wailings after he learns of the missing handkerchief:
Othello, the mighty orator who won Desdemona's hand in court in Act I is reduced to ranting and raving by Act III--all because of jealousy. Othello is like the Beast in "Beauty and the Beast," but instead of love transforming him into a prince, jealousy causes him to become more monstrous.