We used to call this "Hemoglobin". It's something scary complicated, created by elves (as far as you're concerned); no one knows how it works, but it does (bar

We used to call this "Hemoglobin". It's something scary complicated, created by elves (as far as you're concerned); no one knows how it works, but it does (barely), and only if occasional offerings of live virgins are made at its altar. Another appropriate term is "Happy Fun Ball" (google it)