Where is the "Metabolize" spell?

[UndeadDan]

A bunch of the spellbooks in UM reference the "metabolize" spell. I can't find it anywhere. Anyone know where I can find it or is this reference an error?

[Adamantine Dragon]

A note on the PRD lists this spell as "missing." The footnote for "missing" says the item was removed and is no longer official Paizo content.