>In each Pokémon game of Generation I, all Pokémon have an unseen index number used to identify them in the game's ROM. Unlike later generations, the Pokémon are far from being in order by their National Pokédex numbers, and most evolution families are extremely fragmented. In addition, 39 copies of the glitch Pokémon MissingNo. permeate the list, causing the last non-glitch Pokémon, Victreebel, to be located at index 190 instead of the expected 151. Index 0 and indices from 191 to 255 (hex 0xFF) contain all other glitch Pokémon in Generation I. Since Rhydon is located at index 1, many glitch Pokémon will become it upon capture and viewing of their glitched Pokédex entry, known as the Rhydon glitch.