In 1988, with the release of their self-titled debut, L7, these metal-edged punk badasses helped usher in the era of grunge. With a new album in tow, Scatter the Rats (Blackheart Records), 20 years in the making, L7 brought their “Proto Prototype” sludge to the Rialto Theatre on Mother’s Day, May 12.

“We’ve been doing this for 36 years,” announced bassist Jennifer Finch. “And we’re just getting started.” Lead singer/guitarist Donita Sparks added with a smirk, “Saucy grandmothers.”

Demure in stark contrast to the notorious incident at the 1992 Reading Festival, after a raucous crowd, frustrated over “technical difficulties” stalling the band’s set, began to lob mud onto the stage. In remonstration, Sparks countered by removing her tampon on-stage. Throwing it into the crowd, as she yelled, “Eat my used tampon, fuckers!” As the gods of rock sighed.

Albeit, older, these AARP eligible grandmothers are far from being stuck in a “Holding Pattern.” As evidenced on “Dispatch From Mar-a-Lago.” Full of piss and vinegar, this track imagines President Trump tweeting as his beloved country club falls under siege. “Making fun of your government is a tradition older than this country, and that’s what this track is about,” quips Sparks.

Adding to their inscription in the pantheon of rock, L7 unblushingly proclaimed, “I Came Back to Bitch.” And, “Burn Baby” they did.

Mexican garage-punks Le Butcherettes bloodied up the stage first.