Making a Permanent Stat Debuff?

[Practitioner]

I'm a new RPG Maker using MV, and a game mechanic I'm tinkering with is purely item-based stat growth. As part of that, I tried to come up with a 'steroid' item, that would provide a massive buff to a stat, Attack, that would taper off and end with the actual base stat being a point lower-permanently. (This would be complemented by most stat growth in-game coming from various Events and Items, but I ran into this problem before experimenting with it too much.) At any rate, I went to make the item and added four temporary stat buffs, each lasting longer than the last to present the effect of it wearing off slowly, but could not put in a negative number for the permanent stat growth. Is there a way to do this in vanilla RPG Maker MV, or would it require a plugin?

 

[Zarsla]

You could do this using lunatic mode(javascript evals) with Yanfly's Buffs & States Core.