(hex:7E) is a glitch item in Pokémon Red and Blue. It is an unterminated name glitch item, hence is applicable for the Yami Shop glitch.As it is an unterminated name glitch item, it has effects associated with those items, and can be used for screen data exploits like LOL glitch, Yami Shop glitch or will usually cause the TMTRAINER effect in battle.
Using this glitch item with a 0x50 sub-tile early on the screen will result in arbitrary code execution at memory address $D887 in WRAM.
Using it in battle with a 0x50 sub-tile later on the screen (which is usually the case) will typically result in the TMTRAINER effect.