Suggestion: Dwarfism, where a dino is stuck at Sub/ado grow stage.
Explanation: When the bot is added there could be a comand like !sub or !ado depending on what size someone would like, though unless there could also be a "freeze" comand they would probably need to spam the comand in local a lot. Though i would say a requirement for being able to use it is that they hit adult at least ONCE(this could include sub adult) becuse in doing so they could then have there nest placed and useable even if they are at the ado growth, Showing that they are "Adult" just not the right size for it. idk if the reverse Giantisum could be used due to there being no way to actively make your dino bigger then adult, though if anyone had ideas for it i would say that the stats remain the same as an adult even if your bigger.
Pros: More options for defects/disablitys, More relistic as this is a real thing, more rp fun, Challenge for those who would like it.
Cons: People might not like being "weeker" due to there set growth stage(though as its there own choice...), constantly having to clarifie that your adult even though your Ado/sub sized, Work for the admins to set it up with the bot, possible abuse of the comand if it sets growth to a stage could be used to fast grow a dino.