Dagger Cane (3.5e Equipment)
From D&D Wiki
The top of this cane can come off revealing a dagger attached to it.
When drawn this weapon functions like a dagger. Drawing the weapon is treated like drawing a concealed weapon (Standard action w/o Quick Draw). It takes a DC 25 Search check to see that's a weapon. Both the cane and the blade can be masterwork, in addition to the normal +1 Attack, it adds a +5 to the DC to see that's a weapon.