A comparison between the hypergiant star VY Canis Majoris, our Sun and Earth’s orbit.
VY Canis Majoris is so huge that if it was to replace our Sun here in the Solar System, its surface would stretch out beyond Jupiter's, or even Saturn’s, orbit.
Hypergiants like VY Canis Majoris are so massive, that they devour themselves at exponential rates. The amount of energy our Sun emits in year is equal to what a hypergiant would release in the matter of just 6 seconds. It is believed that VY Canis Majoris has already shed half of its original mass, and could literally reach hypernovae at any time, but some astronomers believe that the star has the capability to last nearly another 100,000 years.
Source of the pic and size comparison between Hypergiant Stars: http://www.fromquarkstoquasars.com/behemoths-of-the-universe-hypergiant-stars/