Once upon a time when Ganesha was a small child, he was very naughty and he used to roam about in all the 3 worlds, causing a lot of havoc. This story is one such instance where Ganesha caused trouble to Lord Vishnu himself!!
One day in the Vaikuntha loka, Lord Vishnu was meditating. There was no one around him. It was all peace and quiet until Ganesha came about. He hopped his way into Lord Vishnu’s home and hiding behind a pillar, he peeked at Lord Vishnu. His naughty eyes searched about for something to play with or for something to steal and his eyes happened to fall on the Dharma chakra (Sudarshana chakra) of Lord Vishnu, which was on his hand. The divine instrument that was gleaming, was in the eyes of Ganesha, no more than a “toy”. He crept behind Lord Vishnu without making a sound and patiently removed the Dharma chakra from his hand and silently ran away with it.
As Lord Vishnu was deeply engrossed in his penance, it was quite a while before he realised that his Dharma Chakra was missing. But he soon found out that Ganesha had it, as he was roaming about, playing with it. Lord Vishnu then tried to ask him to return it, but Ganesha was not ready to give it back to him. Upon repeated attempts, Ganesha ate the Dharma chakra and laughed at Lord Vishnu.
He was now at a loss as to what to do and so he changed his method of approach. Lord Vishnu put his hands on his opposite ears and started to move up and down by bending his knees. This amused Ganesha greatly and he started to laugh loudly. In no time, the Dharma chakra fell out of Ganesha’s mouth and Lord Vishnu picked it up and placed it on his finger. Ganesha was frustrated that Lord Vishnu had taken back his “toy” and he went off to some other place to carry out his antics.