Ok, so here are some references in preface to my question:
alchemist’s mutagen if he drinks it. (Although if the other
alchemist creates a different mutagen, the effects of the
“stolen” mutagen immediately cease.)
he can infuse it with an extra bit of his own magical
power. This inflicts 2 points of Intelligence damage
to the alchemist and costs 1,000 gp in rare reagents,
but the mutagen created persists on its own and is not
rendered inert if the alchemist creates another mutagen.
This allows an alchemist to create different types of
mutagens and keep them handy for emergencies. This
does not allow an alchemist to gain the effects of multiple
mutagens—only the most recently imbibed mutagen has
There is a 12th level alchemist (Fred) and 1st level alchemist/11th level barbarian (Hank) in the same party. Fred has the Infuse Mutagen, Feral Mutagen and Greater Mutagen discoveries. He creates both a greater feral mutagen and a greater non-feral mutagen.
Fred drinks his non-feral mutagen. Hank takes Fred's greater feral mutagen and drinks it.
Thanks for your help!