Since their first project as Frost Children (2020’s Aviation Creates Adventurous Beginnings), the duo of Angel and Lulu Prost have honed their chaotic maximalism while helping to define what exactly the “indie sleaze revival” means—is the trend a sound or a feeling? If the free-wheeling, red-blooded party-rock anthems of the St. Louis-raised, New York-based duo are any indication, it’s the latter—drawing from hyperpop, indie rock, electroclash, and meme mischief, Frost Children’s music is hard to pin down, but easy to dance to. On SISTER, the duo wrings every last drop of pathos from a serotonin-heavy blend of scuzzy bloghouse, mid-aughts dance-punk, and festival-core EDM. The spirit of indie sleaze is alive on “ELECTRIC,” with its buzzsaw synths and Rapture-esque vocals, while Kim Petras collab “RADIO” channels sleazy late-2000s electropop. Setting aside their previous work’s occasional tongue-in-cheek humor, the prevailing mood is earnest: On the title track, stripped-down ’90s rock shimmers with a hyperpop sheen as the siblings recall the dandelions and hand-me-downs of their Midwestern upbringing: “The two of us, driving down a roundabout life again/It’s the two of us/Sister.”