Pay Day was at one point planned to be useable as a field move in Generation II.
http://tcrf.net/Pok%C3%A9mon_Gold_and_Silver#Unused_Functions>The list of field moves contains two extra entries:>PAY DAY (ID 00) - apparently this would have been usable outside of battle at one point. Attempting to use it now only crashes the game, as it's been deleted from the pointer table.>ERROR! (ID 15) - the last entry. No other menus have such entries, so this may be a deleted move. Like PAY DAY, this item has no entry in the pointer table, but by chance the game manages to not crash and simply does nothing when this is used.>The pointer table for the abilities also shows some interesting facts:>The table is in fact a map (unordered ID->pointer pairs), rather than an array. The reason for this is not clear.>The game checks for a terminating entry in this list (pointer 0000); if it finds this entry before the ID it's looking for, it will just return without doing anything. However, the list doesn't actually have a terminating entry, so Pay Day and Error will cause it to read past the end of the list looking for them, eventually finding an invalid pointer for Pay Day and a terminating entry in the following data (thus why Error does nothing).>The out-of-order keys suggest that Waterfall was added later in development; it appears near the end rather than being grouped with the other HM moves.>To see the unused menu options, enter one or both of the following GameShark codes and select a Pokémon with one HM ability: 0100D5D0 for Pay Day, 0115D6D0 for "Error!". 