When eaten, it acts as all the ommel-extracts together (ommel cerumen, ommel tears, ommel sweat and ommel snot), thus boosting all the stats up by 1 point. It will also give you Overfed status for a very long time.
When in a great peril, it can be zapped. What, why so surprised, everybody knows that a banana is zapable! It acts as a wand of fireballs but and always has only a few rounds6 charges.
When carried around, it emits strong light, thus making a good light source. Well, you can probably find out a better way to use it, cant you?