The sacrifice of Iravan

Iravan, the son of Arjun and naga princess Uloopi, sacrificed himself to goddess Kali to ensure the victory of his father and his team in the Kurukshetra war. He however, had a last wish – He wanted to marry a girl before he died. Now, getting a girl who knew her husband would die in few days was a tricky task. So, Lord Krishna took the form of Mohini, married Iravan and even wept like a widow after her husband died.