Super Giant

Introduction
Giant are among us in The Universe. The Giant Stars overpower in size that of The Sun bigtime. The Giant Stars themselves though, are not even the biggest, for they are too overpowered in size by Super Giants! Supergiants are as big as it gets, becoming so big that they either become Supernovae, Neutron Stars or Black Holes. There are two types of Supergiants, Red Supergiants and Blue Supergiants. Just like Giants are split into Blue and Red, so are Supergiants!
Blue Super Giant
Blue Supergiants are blue, of course, are extremely fierce in the sense of high temperatures and have a very high luminosity. In fact that are around 10,000 to One Million times brighter than The Sun. Blue Supergiants have a surface temperature of 10,000 Kelvin to 50,000 Kelvin or 9727 degrees Celsius to 49727 degrees Celsius or 17540 degrees Fahrenheit to 89540 degrees Fahrenheit. For a Main Sequence Star to become a Blue Supergiants it has to fit the following criteria: 10-300 Solar Mass ( A Solar Mass is equal to 1.989e+30 Kilograms, 4.385e+30 Pounds, 2.192e+27 Us Tons or 1.989e+27 Metric Tons) and be an O class or B class star (a B type star is a yellow star similar to The Sun, an O type Star is blue-white star with the spectral type O and are 10,000 to 1 Million times the size of The Sun.). These stars will evolve from their main sequence state and compose of heavier elements and expand continuously. Four examples of Blue Supergiants are UW Canis Major, Rigel, Zeta Puppis & MACS J1149 Lensed Star 1 also known as Icarus. 
Red Super Giant
Larger than Blue Supergiants are Red Supergiants. Red Supergiants, by volume, are the biggest stars in The Universe. Their luminosity class is spectre type K or spectre type M. Despite their size, Red Giants are relatively cold compared to other stars, with a surface temperature falling below 4100 Kelvin (3827 degrees Celsius or 6920 degrees Fahrenheit). The Mass of Red Supergiants are 10 Solar Masses to 40 Solar Masses (1.989e+31 Kilograms to 7.956e+31 Kilograms, 4.385e+31 pounds to 1.754e+32 Pounds, 2.192e+28 US tons to 8.77e+28 US tons, 1.989e+28 Metric Tons to 7.956e+28 Metric Tons). Red Supergiants have a Solar Radius (R) of 264R to 303R (1.837e+8 Kilometers to 2.108e+8 Kilometers or 1.141e+8 Miles to 1.31e+8 Miles). One other characteristic of Red Supergiants are their slow rotational patterns. The minimum rotation velocity of a Red Supergiant is 5 km/s (Kilometers per second) This is still faster than a bullet, but compared to other stars, this velocity is relatively slow. Betelgeuse, a Red Supergiant, for example takes around 30 Earth Years to complete a entire rotation. Other examples of Red Supergiants are VY Canis Majoris, Mu Cephei & KW Sagittarii. 
Supernova
Supergiants, Red & Blue become Supernovae when they die. One example of a Supernovae that was once a Blue Supergiant is Supernova 1987A who is a Type 2 Supernova.
Conclusion
What Supergiants and giants teach us is that, there is always someone bigger and better than the one who is bigger and better than thee. Even Giant Stars, themselves larger in their own respect, are dwarfed in comparison to Supergiants. However, being bigger isn't always an advantage. Red Supergiants for example are slower than other stars by a significant margin. This is true for all thing, living or nonliving.