Ghatotkacha, when he was young, lived with his mother Hidimbaa, when one day he had a fight with Abhimanyu, his cousin, without knowing that Abhimanyu was Arjuna's son. The telugu movie Mayabazar is based upon this fight and Ghatotkacha's subsequent help to Abhimanyu in winning the hand of Balarama's daughter, Sasirekha.
Ghatotkacha is considered to be a loyal and humble figure. He made himself and his followers available to his father Bhima at any time; all Bhima had to do was to think of him and he would appear. Like his father, Ghatotkacha primarily fought with the mace.
His wife was Ahilawati and his son was Barbarika.
In the Mahābhārata, Ghatotkacha was summoned by Bhima to fight on the Pandava side in the Kurukshetra battle. Invoking his magical powers, he wrought great havoc in the Kaurava army. In particular after the death of Jayadratha, when the battle continued on past sunset, his powers were at their most effective (at night).
At this point in the battle, the Kaurava leader Duryodhana appealed to his best fighter, Karna, to kill Ghatotkacha as the whole Kaurava army was coming close to annihilation due to his ceaseless strikes from the air. Karna possessed a divine weapon, or shakti, granted by the god Indra. It could be used only once, and Karna had been saving it to use on his arch-enemy, the best Pandava fighter, Arjuna.
Loyal Karna, unable to refuse the request of Duryodhana whose cause he had pledged himself to serve, hurled the missile at Ghatotkacha, killing him. This is considered to be the turning point of the war. After his death, the Pandava counselor Krishna smiled, as he considered the war to have been won for the Pandavas now that Karna no longer had a divine weapon to use in fighting Arjuna.