You can come up with the harmless effects on your own!

Our "no homebrew" rule is really just to prevent totally made-up classes/species, so everyone can have a relatively even playing field, to make it easier for people new to D&D to adapt to the setting. What you're describing is more of a narrative choice, so feel free to make up harmless effects so long as they don't wildly change the core aspect of your class/species/spell list/etc.