This article lists Game Genie codes for Pokémon Crystal.
Pokémon Crystal does not normally work on a physical Game Genie.
Change Marill's cry base to the unused base cry: (credits: ChickasaurusGL)
XXB-D09-E6E (upper length value)
XXB-CF9-6EA (lower length value)
XXB-CE9-E6E (echo value)
XXB-CD9-806 (pitch value)
Values of all $00 except for pitch as $FF will give a cry that sounds like the typical interpretation from the The Cutting Room Floor example.