(hex:C3) is a glitch item in Pokémon Yellow.It is the last glitch item in index order before glitch items TM51 (hex:FB)-TM54 (hex:FE) and Cancel (hex:FF).
It is not an unterminated name glitch item but still causes one A/B-press of lag upon when the player opens a menu containing it.
If it is used outside of battle, this glitch item causes Professor Oak's message that it isn't the time to use the item. If used in battle, it will function as a stat-stage raising item and its quantity will be decreased, but there will be no other effect (the game will state "Nothing happened!").