Acid Satan is a five-piece metal and punk fusion band from La Rioja, Argentina, formed in early 2023, featuring Kevin Satan on vocals and guitar, Mati Argonaut on guitar, Neri Blackmass on keys and vocals, Pablo Fat Pipe on bass, and Pablo Kdk on drums. Their debut EP "Doomed Junkies," released September 28, 2023 and recorded in the Matadero neighborhood of La Rioja, contains six tracks exploring themes of witchcraft, paranoia, and dark psychedelia. The band fuses crossover thrash energy with stoner heaviness and lysergic textures uncommon in Argentina's northwest.

Acid Storm is a thrash metal band from São Paulo with roots stretching back to 1986, when they operated under the name Exterminator in the city's northern suburbs before reforming under the current name in 1989. Their second album, Biotronic Genesis (1991), is regarded as a classic of Brazilian technical thrash metal, drawing comparisons to Testament and Forbidden with sci-fi and warfare lyrical themes. The band reunited in 2020 and continues to carry the torch of São Paulo's veteran underground thrash scene.

Acid Trip is a four-piece progressive and stoner metal band from Valdivia, Chile, formed in 2010, comprising Felipe Mendoza (guitar/vocals), Sergio Hinojosa (guitar/vocals), Nicolás Mendoza (bass/vocals), and Felipe Valencia (drums/vocals). Their debut album "Volumen Uno" was released on December 9, 2024, recorded at Estudios MonteRanco in Futrono, and features singles including "Hombre Elefante," "Mary Jane," and "Cabalgata en el Apocalipsis." The record received positive reception across the Chilean metal and rock press.

Acidemia is a stoner/doom trio from Lages, Santa Catarina, Brazil, formed by Henrique Soares (bass/vocals), Mateus Varela (guitar), and Thiago Granetto (drums), drawing heavily from Electric Wizard and Monolord. Their 2021 album Podridão marked a shift toward compositions entirely in Portuguese, blending sludge-inflected doom with psychedelic heaviness across seven tracks. The band has been featured on the Weedian-curated Trip to Brazil compilation, placing them among the notable voices in Brazil's growing stoner/doom underground.

Acrament was a death metal band from Santiago, Chile, active from the early 1990s until their split. The band's lineup included Christian Asenjo on vocals and guitar, Daniel Muñoz on lead guitar, Dario Díaz on bass, and Luis Pinto on drums. Their 1995 promotional demo "Lands of Blood" stands as their sole documented release.

Acrimonious is a technical death metal band from Concepción, Chile, with roots going back to 1991 under the name Crematory before adopting their current name in 1992. The band released the full-length "Crisis de Odio" in 2005 and the EP "Infierno Terrenal" in 2017, both recorded in Concepción, along with the demo compilation "Unburied Past" in 2020. Their current lineup features Mauricio Cea on vocals, Jorge Matus and Danilo Garcia on guitars, Raúl Seguel on bass, and Patricio Lepe on drums.

Acrostic are a thrash metal band from Viña del Mar who describe their sound as "Noisethrash" — a blend of old-school thrash, hardcore punk, and crust rooted in the Bay Area and European thrash traditions. The trio of Janito Attack, Pablito Attack, and Pelao Attack released their full-length "Sincretismo-Posguerra" in November 2016 on Underground Defenders Records, a 11-track record recorded at JRP Studios in Viña del Mar and limited to 500 copies.

Acrópole is a black metal band from Rio Brilhante and Dourados in Mato Grosso do Sul, active since 2020. Based deep in Brazil's interior rather than in the traditional urban metal centers, the band operates in the raw, atmospheric tradition of Brazilian black metal, contributing to what is a notably sparse but growing extreme metal presence in the Mato Grosso do Sul state.

Acsa is a heavy metal band from Cipolletti, in the Patagonian province of Río Negro, Argentina, formed under their current name around 2014 after originating as Pucara in 2009. The band's lineup of Javier Burgos on vocals, David Ariel Rodríguez on guitar, Damián Zeballos on bass, and Alejandro Rodríguez on drums recorded their debut album "Sangriento Final" at Horus Estudio in Cipolletti in 2021. Their sound draws from the classic Argentine heavy metal tradition while aiming for a heavier, more original direction.