There have been over 90 recorded cases of amphibians being found alive but fully encased in coal pockets or stone geodes. Of these cases, 40 involved frogs or toads. After a few minutes exposed to air it comes-to-life In most cases the animal dies with 24-72 hours but there are some references that when these poor creatures were quickly allowed into fresh pond water they seem to have survived indefinitely.
Necromancer a couple millenia ago was just like.
" you know what’d freak some miners out?"