*How many times do I have to teach you this lesson, Hex, man!*

*Why don't you read this handy, updated manual called *Mask's updated lore* that clearly describes glass is not his weakness. It just slows down his corrosion. This corrosion is what you should be worried about. It degrades organic material like flesh until nothing remains, as well as solid concrete walls and glass. Glass will degrade more slowly. And I will possess anyone! Same with Masque. Once I'm on you, I have attached onto you like a leech. Attempt to remove me and risk damaging your giga-chads' faces* Mask

*Forgot me already? My brother must have weak memory. I have hurt Mask physically. You haven't been able to, Undyne hasn't been able to, sans hasn't, Alphys hasn't. You need something like me. But just remember Hex, where my brother's power ends... *malicious smile* mine begins...* Masque.

"It degrades organic material"

Flare:

Is concrete organic or are you saying you are organic?

Yeah. I can (as mask) control it for the most part, but when its given free rein, it flows nonstop. anyone and anything caught in its touch will be affected, plus after a certain time appendages will form and try to grab friend and foe alike...

Flare is not organic. He has plasma with a living form.

Good. an excellent source of heat!

Does the corrosion do anything to me in this case?

To plasma no, but if it somehow reaches your core, welp. You are doomed

Well, if we remember the genocide fever dream, I guess the corrosion can shrivel me up, but no severe damage.

Yep. Hex, on the other fin...

yummy organic beans-