(hex:B6) is a glitch item in Pokémon Red and Blue.It is an unterminated name glitch item, hence provides the effects associated with those glitches and allows for glitches such as Yami Shop glitch and LOL glitch.
If a 0x50 sub-tile is early enough in the saved screen data, then this item will act as a Rival's effect glitch item which opens the menu from both in and outside of battle. From outside of battle, if the player exits the menu with B they can enter a glitched state where they can walk through walls that are one tile thick. If the player selects a Pokémon without full HP instead, it will heal up to 80 HP and use up one of the item.
This glitch item can be used as a healing item for up to 80 HP within battle if a 0x50 sub-tile is forced early in the saved screen data with GameShark code 0150A0C3 (or theoretically OAM DMA hijacking).