Question: Which was formed first, Alice in Chains or Car Seat Headrest?

Context paragraphs:
Car seat: A car seat is the seat used in automobiles. Most car seats are made from inexpensive but durable material in order to withstand prolonged use.  The most common material is polyester.

Twin Fantasy: Twin Fantasy is the sixth studio album by indie rock act Car Seat Headrest.  Since its release in 2011, the album has amassed a cult following.

Teens of Denial: Teens of Denial is the tenth studio album by American indie rock band Car Seat Headrest.  It was released on May 20, 2016 by Matador Records, serving as the band's second album for the label and the first to consist of newly recorded material.

Diono: Diono is an American company that manufactures child safety seats as well as travel, stroller and car seat accessories.  Based in Sumner, Washington, Diono was founded in 1999 as Sunshine Kids Juvenile Products.  It introduced a device to tighten seat belts used with car seats to the industry and holds various patents.

Alice in Chains: Alice in Chains is an American rock band formed in Seattle, Washington, in 1987 by guitarist/vocalist Jerry Cantrell and drummer Sean Kinney, who then recruited bassist Mike Starr and lead vocalist Layne Staley.  Mike Starr was replaced in 1993 by Mike Inez.

Teens of Style: Teens of Style is the 9th studio album by American indie rock band Car Seat Headrest, released on October 30, 2015.  It was their first album recorded for Matador Records.  Intended as an introductory compilation for new listeners, it features reworked newly recorded versions of songs originally released between 2010 and 2012, with the addition of one new composition.

Car Seat Headrest: Car Seat Headrest is an American indie rock band originally from Leesburg, Virginia, United States, currently based in Seattle, Washington.  Begun as a solo recording project in 2010 by Will Barnes (born August 23, 1992), known professionally as Will Toledo, Car Seat Headrest released 12 albums on the music platform Bandcamp.  Signed to Matador Records in 2015, Car Seat Headrest began a tour in 2016 presenting material from their latest album "Teens of Denial" as a full band.  Toledo's work is notable for its large online cult following.  The group has received attention from publications including "Pitchfork", "Rolling Stone", "The New Yorker" and "Paste", amongst others.

Child safety seat: A child safety seat (infant safety seat, child restraint system, child seat, baby seat, restraining car seat, car seat, etc.) is a seat designed specifically to protect children from injury or death during collisions.  Most commonly these seats are purchased and installed by consumers, but car manufacturers may integrate them directly into their vehicle's design and generally are required to provide anchors and to ensure seat belt compatibility.  Many jurisdictions require children defined by age, weight, and/or height to use a government-approved child safety seat when riding in a vehicle.  Child safety seats provide passive restraints and must be properly used to be effective.  However, research indicates many child safety restraints are often not used properly.  To tackle this negative trend, health officials and child safety experts produce child safety videos to teach proper car seat installation to parents and caregivers.

Gaming chair: Gaming Chair is sporty designed chair specially for gamer's comforts.  The history of the gaming chair originated from racing games such as Need For Speed, FlatOut, Dirt, etc.  The original idea was to replicate the feel you have when driving a sporty car.  This is why almost all gaming chairs are designed to look like a car seat.  They have very high backrests and flared out sides.  The sides of the seat will typically have additional padding.  The sides of the backrest will be slightly curved inward.  Most Models will also have some type of cutouts in the backrest to help add to the sporty look.

Alice N' Chains: Alice N' Chains was an American glam metal band from Seattle, Washington formed in 1986 by former members of Sleze.  Towards the end of their run as Sleze, discussions arose about changing their name to "Alice in Chains".  However, due to concerns over the reference to female bondage, the group ultimately chose to spell it as Alice N' Chains.  They performed under this moniker over about a 12-month period and recorded two demos before breaking up on friendly terms in 1987.  One of its members, Layne Staley, ultimately took the name that he and his former bandmates had initially flirted with when he joined a different group a few months later that ultimately became known as Alice in Chains.

Supporting paragraphs: Alice in Chains Car Seat Headrest
Answer: Alice in Chains