(hex:89) is a glitch item in Pokémon Red and Blue.
When it is used both in and outside of battle, it will open up the Pokédex (the same effect as Pokédex (glitch item)).
If this glitch item is used in battle, then upon closing the menu a turn will be used up and the graphics will be affected. Specifically both of the user and opponent's sprites will be replaced with overworld graphics and HP bars may be replaced with letters.