In the book "Living for Pleasure: An Epicurean Guide to Life" there is the usage of the word "corrosive" for the "unnatural/unnecessary" category of desires. We have likely discussed this before, but it is worth bringing up again.
I would recommend against using the word "corrosive" for several reasons:
1) It gives a situation a kind of static state that sounds difficult to remedy (once something is corroded it is difficult to restore it back to its original nature), where as the truth is that the human mind can shift rather quickly out of the "unnatural/unnecessary" when realizing the truth of something.
2) It sounds overly "dramatic" (envisioning leaking battery acid that corrodes metal). And it attributes an aweful lot of power to desires, making them sound dangerous or "evil" (it almost has a "Christian puritanical" sound to it). But if you dig down to see what is going on then you will see that there are basic needs hiding deep below the surface (below the "unnatural" desire), but it is actually the strategy for meeting those needs isn't the best strategy. (Needs for safety, security, reassurance, or knowledge could be the deeper needs).
3) It doesn't accurately describe the biggest problem for things that are "unnatural" -- the main problem is that they are "empty" of happiness and pleasure (and that they cause more pain than pleasure).
----I think most people here on the forum would understand that "natural" is something that nature gives to animals or occurs naturally for animals. Where as, "unnatural" is something which is only an opinion with no basis in nature. Once we are clear about what these categories are, then we can decide how best to label them.
My own current take on the three categories of desires:
1) natural and necessary for well-being
2) nice to have but optional
3) empty, painful, or leading to unwanted consequences