"Its body temperature is roughly 18,000 degrees F. Flames spout from gaps in its hardened shell." ~ Magcargo's Black and White (2) Pokédex entry.
By logic, the sun has a surface temperature of 5,778 kelvin. If you do the math, 5,778 kelvin = 9,940.73 degrees Fahrenheit.
This shows that, if Pokémon were real, any person would die immediately if they got too close to Magcargo.