Think twice before taking on the vintage band T-shirt trend — at least, if you’re anywhere in the vicinity of Twisted Sister’s Dee Snider.

The rocker took to Twitter earlier this week to vent about nonmetal fans wearing vintage metal band T-shirts.

For Snider, it’s “sickening” and disrespectful to wear band merch unless you’re a true fan of the group.

Evidently, Snider doesn’t appreciate how awesome vintage band tees look on fashion heavy hitters, including the likes of Kendall Jenner, Alessandra Ambrosio and Hailey Baldwin.