Big? Big.

From WIMP.

So we start with the planets in our solar system, move up to our sun and then other stars which just keep getting bigger and huger and ever more gigantic until we get to VY Canis Majoris which is the largest star in the known universe. Seems I've heard of this story before, so I go read a little bit. He's big alright:

Placed at the center of the Solar System, VY Canis Majoris's surface would extend beyond the orbit of Saturn. 

But he's not that tough:

the star is a thousand times less dense than the atmosphere of the Earth. 

Maybe not that tough, but his ginormous size more than compensates:

Astronomers . . . have predicted that VY Canis Majoris will explode as a hypernova within the next 100,000 years. Theoretically, a hypernova would cause gamma ray bursts that could damage the contents of the local galaxy, wiping out any cellular life within a number of light years; however, no hypergiant is located close enough to Earth to pose a threat. The star is large enough to create an enormous black hole, and it is very likely to do so.