Ganesha

In Hinduism, Ganesha (Gaṇeśa, "lord of the hosts," also spelled Ganesa and sometimes referred to as Ganesh in Hindi, Bengali and other Indian vernaculars) is a son of Shiva and Parvati, and the husband of Bharati, Riddhi and Siddhi. In art, he is depicted as a pot bellied yellow or red god with four arms and the head of a one-tusked elephant, riding or attended to by a mouse). Typically, his name is prefixed with the Hindu title of respect, 'Shri.'
Ganesha acquired his head through varying methods in different stories. In one, Shiva decapitated him because Ganesha refused to allow him to enter the bath while Parvati was bathing. Shiva had to give him the new head to placate his wife. In another version, Parvati showed the child off to Shiva, whose face burned his head to ashes, which Brahma told Shiva to replace with the first head he could find—in this case, that of an elephant. The lack of a second tusk is explained by different stories. An avatar of Vishnu, Parashurama, once went to visit Shiva but the way was blocked by Ganesha. Parasurama threw his axe at him and Ganesha, knowing the axe had been given to him by Shiva, allowed it to cut off one of his tusks. Yet another myth is that, in the process of writing the Mahabharata (at the dictation of Vyasa), Ganesh found that his pen had broken, and in the urgency of taking down the great words, snapped off his left tusk as a replacement quill.