If the character appears as a blank square or crashes the game, it may be intended for an older or newer version of the engine than the one you are running. If you'd like to dive deeper, I can explain: How to fix common crashes when adding new characters. Where to find Ikemen GO for a more modern experience.
These suffixes often denote specific "adult" or enhanced versions of character animations and assets within the modding community. mugen-h-slime-plus
It is classified as an "H-character," meaning its moveset focuses on explicit animations rather than traditional competitive fighting. Attack Patterns: If the character appears as a blank square
: Transformation, slime inflation, and "lose" animations. and "lose" animations.