Science
This highly flammable element is the primary fuel that stars burn during main-sequence fusion.
What is hydrogen?
Calculated as the ratio of a circle's circumference to its diameter, this irrational number has its own celebration day every year on March 14th.
What is Pi (π)?
In the popular sandbox game Minecraft, what is the name of the hostile, floating mob found only in the Nether that shoots explosive fireballs?
What is Ghast?