Curse

Lohitang knew a secret of Lord Vishnu. The secret was,when Lord Narasimha killed Hiranyakashyap,he was so angry and trying to destroy the Earth. Lord Shiva stopped him to do that. Rishi Kashyap was very angry on Vishnu and gave a curse to him that one day anyone will swallow Lord Vishnu. When Lohitang heard the secret of Vishnu,after some days Lohitang had sent a demon whose name was Nigas. Nigas had a swallow power with him that Lord Brahma gave him. Nigas loved Shiva and worshipped him everyday. One day he swallowed Lord Vishnu with his powers. Lord Shiva went under the world and Lord Dattatreya rescued him and after some days Shiva killed Nigas and rescued Lord Vishnu.

https://en.wikipedia.org/wiki/Devon_Ke_Dev...Mahadev
http://www.hotstar.com/search?q=Mahadev