This is the latest sign of alien activity in the skies above Merton.
The picture was taken by Nicholas Fitter, from his flat on the Broadway last week.
Mr Fitter said: “I was doing my laundry when I saw it.
"I thought it was a balloon at first, but it was as big as a house. I went out on the roof and took some pictures.
“It had tentacles that appeared squid like and even mimicked a squids movement at times. I am sure other people would have seen it too since this jellyfish appeared rather large in broad daylight.”
Another possible UFO sighting was reported by Tina de Souza in Mitcham.
The Cheam resident was driving down Love Lane with her son when the pair spotted unusual lights in the night sky.
“They were moving about all over the place,” she said.
Speculation about alien activity in Wimbledon and Colliers Wood began two weeks ago, after a number of possible sightings in the area.
• Have you seen any UFOs? Let us know by email or phone the newsroom on 020 8330 9555.