Animalize is the twelfth studio album by American rock band Kiss. It was released on September 13, 1984, by Mercury Records. The album marked the only appearance by lead guitarist Mark St. John, who replaced Vinnie Vincent in April 1984.

At this point in Kiss's career, the band had lost two founding members, drummer Peter Criss and lead guitarist Ace Frehley, released two unsuccessful albums that largely alienated their fanbase (1980's Unmasked and 1981's Music from "The Elder") and made a "return to form" with 1982's Creatures of the Night that still failed to gain the public's attention. However, the sessions for Animalize saw the band regaining momentum, as 1983's Lick It Up had achieved Platinum status and yielded a successful tour. With the departure of another member in lead guitarist Vinnie Vincent and the hiring of a complete unknown in Mark St. John to replace him, Animalize saw the band at a crossroads of sorts.

At the time of the album's recording, vocalist/bassist Gene Simmons was pursuing a career in acting and was largely absent from Kiss. Vocalist/guitarist Paul Stanley later said, "I felt abandoned when it came time to make Animalize. After informing me without any warning or discussion that he wouldn't be around for the album, Gene went into a studio and crapped out some demos as fast as he could. Then he was off to do a movie." Stanley had become Kiss's de facto leader and he was left responsible for songwriting, production and direction of the new album.

Simmons' relationships with his bandmates were at an all time low during this period. Most of this centered around his perceived lack of commitment to the band and his preoccupation with numerous outside projects, including producing and managing other rock groups such as Black 'n Blue (of whom future Kiss bandmate Tommy Thayer was a member at the time), and co-starring in the 1984 movie Runaway.^{[citation needed]}

Entering the studio to record Animalize, newly hired lead guitarist St. John clashed often with his new bandmates, with Carr saying years later that St. John's talent led to a very arrogant demeanor in the studio. A disagreement over a bass part which bassist Simmons had asked St. John to record for the album left both Simmons and Carr furious with the new guitarist, with Stanley and Simmons later taking St. John aside to warn him about his bad attitude. According to St. John himself, Stanley and Simmons got "all kind of weird" over what he was recording in the studio, with Stanley saying that his playing had no structure and that the guitarist was "just puking notes" and could never play the same thing twice. Bruce Kulick, future Kiss member and brother of former Kiss-collaborator Bob Kulick, was eventually brought into the studio to play a guitar solo on the track "Lonely Is the Hunter" & opening guitar intro for "Murder in High-Heels".

Along with songwriter Desmond Child, Stanley gave the band its biggest hit single in years with "Heaven's on Fire". On top of production, Stanley claims to have personally handled everything from naming the album to marketing and "cajoling MTV".

In retrospective reviews, Matthew Wilkening of Ultimate Classic Rock described Animalize as "Kiss' most aggressive album ever" with some tracks "bordering on metal territory with their heavily distorted, uptempo attack." Greg Prato of AllMusic observed that "Kiss seemed to be copying other successful pop-metal bands (Bon Jovi, Def Leppard, Mötley Crüe, etc.), both musically and visually" and concluded that the album, despite having a few good songs, wasn't as strong as its two predecessors, singling out most of Simmons' contributions as "forgettable" and "embarrassing".

Guitar World magazine later placed the album on their list of "New Sensations: 50 Iconic Albums That Defined 1984".