The Houston Astros ain't safe from getting totally roasted for their sign-stealing scandal ... not even by NHL mascots!!

The Philadelphia Flyers' beloved freakish-lookin' thing named Gritty took a jab at the 'Stros during the team's 3-0 over the Pittsburgh Penguins on Wednesday ... using a trash can with Houston's logo to pump up the crowd.

On top of that, Gritty had a guy stand next to him while holding a sign that read "Gritty learnt this from the Astros."

Boom. ROASTED.

Of course, investigators concluded the Astros banged on a trash can to tip-off batters on which pitches would be coming their way ... ya'know, like cheaters do.

Alex Cora -- who was Houston's bench coach at the time -- stepped down from his gig with the Red Sox, A.J. Hinch and GM Jeff Luhnow were fired, and Carlos Beltran stepped down from the Mets' managing job as well.

While there have been major punishments handed down by MLB, it's been open season on the Astros for those using humor to cope with the cheating.

As for Gritty ... the dude has always been ruthless. Remember when he made his shot at P.K. Subban's fiancee, Lindsey Vonn??