Agent Smart
You would think that some of us would realise by now not to try drinking strange liquids, particularly those found around paralysed bodies, or in dungeons of doom. That doesn't stop us from trying, though.
The party found some vials of liquid after exploring one of the many rooms in the dungeon, and the Mage wanted to identify the liquids inside using Spellcraft, which means having a small taste in the process. I suppose we could have stopped him, but we didn't. He has to learn on his own.
He dabbed his little finger in to the vial and took the smallest of tastes of the liquid, at which point the DM asked him to make a saving throw. Let's just say it was lucky we had some Lesser Restoration spells learnt.
The funny bit was that the Mage was boasting only minutes earlier how high his Intelligence was. Sure.