This is an old item that seems to have been forgotten. I can see why. I'm not a fan of save or die, even if it's to gain +1 to Intelligence or Wisdom. The fact that the original item could be consumed multiple times (with that pesky save vs poison or DIE) rather limited how much PCs were willing to tempt fate. Not often I can assure you. I like the idea of eating an egg to gain +1 to Intelligence, but there are better items that can raise your Intelligence that may cost a tad more but with no risk at all. Food as treasure is tough because often the bonuses are temporary, especially with magical food. I wanted this to be a little more appealing. Feedback would be really helpful. DMs -- would you ever use this?
Egg of Reason
Updated from the AD&D item of the same name.
An egg of reason is always coated with unguent of timelessness. Although very old and quite vile smelling, each egg has the possibility of increasing the eater's Intelligence or Wisdom. However, an individual who consumes an egg of reason must first succeed on a Fortitude saving throw (DC 17) or take 2 points of ability drain to the same ability the egg would have conferred. This drain cannot be removed by magic or supernatural means until 48 hours have passed. Creatures that are immune to ability drain cannot benefit from eating an egg of reason. The eater still gains the +1 resistance bonus to the save from the unguent of timelessness that coats the egg. If the save is successful, the eater gains a +1 Circumstance bonus to either Intelligence or Wisdom.
Once the eater has gained a benefit from an egg of reason, he cannot benefit again from eating additional eggs of reason, though he must still make the saving throw to avoid taking the 2 points of ability drain (see above). If the unguent of timelessness is removed from the egg before it is consumed, the egg becomes safe to eat but loses its ability-enhancing property.
Faint Transmutation; CL 5th; Craft Wondrous Item fox's cunning or owl's wisdom; Price 6,150 gp. Weight --
[Final Edit] Increased cost in keeping with other magic items.