Splattack!

Splattack! is a song performed by Squid Squad.

Description
Splattack! is an one of the 5 multiplayer songs released with Splatoon at launch. Like all battle songs, it has a random chance of being played during online matches. Like most Squid Squad songs, Splattack! is a fusion of rock and electronic music, with an emphasis on the backing drums and prominent guitar riffs, but also features singing in the inkling language. In addition to multiplayer matches, it can also be heard in Squid Beatz. In Splatoon 2, Splattack! can be unlocked to listen in Squid Beatz 2 from the  amiibo. It however cannot be heard anywhere else in the base game. The song is also featured in the soundtrack for Super Smash Bros. Ultimate, along with a remix (see below).

Splattack! (Jam Session)
The Jam Session is a remix of Splattack! that plays during the Tutorial. However after completing the Tutorial, it can no longer be heard anywhere in the game. It does not appear Squid Beatz but it does appear in Splatune. It has a more prominent bass than the original and although it has a minimalist start, more instrumentation is added as the track progresses.

Splattack! (Inkredible New Stages and Gear)
A remixed version of Splattack! played during the first half of the Inkredible New Stages and Gear trailer released on the 12th of November 2015, while announcing Museum d'Alfonsino. It features a classical style intro to suit the museum theme, before transitioning into a composition more like the original version. It is not used anywhere else other than the trailer. The song stops when the second half of the trailer begins, announcing Mahi-Mahi Resort and uses Shellfie. The backing soundtrack to the entire trailer without any SFX was released in the Splatoon Live in Makuhari album, which also includes the second half playing Shellfie.

Splattack! (New Stage Squid Dance)
Another Splattack! remix used exclusively in a trailer, this version played during the New Stage Squid Dance (Piranha Pit & Ancho-V Games) trailer. It features a very similar composition to the Jam Session version, but also has a lot of Inkling sound effects incorporated into the tune. It too appears in Splatoon Live in Makuhari.

Splattack! (Octo)
Octo Expansion features the proper return of the Splattack! song in Splatoon 2, with a remix known as ''Splattack! (Octo)''. This is now performed by Dedf1sh in-game, who has remixed the original from Squid Squad. It is played during Spinal Phase, where Agent 8 battles Agent 3. It's resembles a glitched version of the regular song, transforming it into a purely electronic song, rather than the rock fusion of the original. A sample from the intro of I Am Octavio can be heard. It can also be heard in Squid Beatz 2 and Octotune.

Splattack! (Super Smash Bros. Ultimate Remix)
Arranged by the Taito Corporation, and supervised by Shohei Tsuchiya (ZUNTATA), a new Splattack! remix was composed for use in Super Smash Bros. Ultimate. The song now has a jazz-like composition, with the use of trumpets and saxophones, rather than the rock sound of the original. It also includes the melody from the Now or Never and the Opening song that plays when starting a match. By default it has the song with the highest chance of playing in the Moray Towers stage, and it can also be heard in the Sounds section in the Vault menu.

Splattack! (E3 2014)
During the initial reveal trailer for Splatoon, an early version was used. It was rougher than the final version, with a louder emphasis on vocals, which had a slight echo and was re-recorded for the final cut. The intro (which was moved in the final version) appears to resemble the opening of a live performance, as it features what appears to be a crowd chanting. It appears on Splatune.

Splattack! (Single Player Trailer)
The early E3 version of Splattack! was once again used in the beginning of the Splatoon Single Player Trailer. The song is mostly the same as the E3 version, but a radio-esque filter has been added to emphasise the contrast between the multiplayer and single campaigns, and to signify the warfare-like theme of Octo Valley. A similar effect is used on Sheldon's version of Lookin' Fresh. Due to the nature of it being an intro, it is very short, playing for only 16 seconds before it transitions into Tentacular Circus for the rest of the trailer.

Splash Screen music
During the startup screen for Splatoon, the percussion line from Splattack! plays.

Shooting range music
In the Shooting Range, a version of the ''Splattack! Jam Session'' plays. It is a looped version of the beginning of the Jam Session version. It does not appear in Squid Beatz or any Splatoon soundtrack.

Agent 3 Appears!
In the Octo Expansion, when Agent 3 responds to Agent 8's CQ-80 distress signal activated by Marina, and jumps out of the roof of Central Station to save Agent 8 and Cap'n Cuttlefish, the ''Splattack! (Jam Session)'' plays very briefly until Agent 3 gets knocked out. Known as Agent 3 appears, this version is mostly the same as the original, but only lasts 16 seconds long. The version extracted from the game still has the sound effects of Agent 3 smashing the glass of the roof and the blender. This version does not appear in any Splatoon soundtrack.

Inkoming! (Splatoon 2 Reveal Trailer)
The song Inkcoming! by Wet Floor was played during the initial reveal trailer of Splatoon 2 at the Nintendo Switch Presentation. During the end of the trailer, a series of notes that make up the melody of Splattack! can be heard. This outro is not heard in any other version of Inkcoming!, not does this version appear in any Splatoon soundtrack.

Trivia

 * Splattack! is considered the theme tune of Splatoon game, with the song being played during the initial reveal trailer for Splatoon. It's the first song on Squid Beatz, and among the first on Splatune and Splattack! and its variants has played in multiple trailers and commercials for Splatoon, more than any other song.
 * Splattack! can also be seen as the theme tune for Agent 3, due to their prominent role in Splatoon. In the Octo Expansion, during major scenes featuring Agent 3, such as when they save Agent 8 and Cap'n Cuttlefish, or when Agent 8 battles a Sanitized Agent 3, a version of Splattack! plays in the background.
 * Inkoming! could be seen as the theme tune of Splatoon 2, and therefore shares the fact that both theme tunes of have an exclamation mark at the end.
 * A behind the scenes video was released showing the recording of Splattack!, however the video itself uses the final recording instead of the raw performance. The Jam Session version was also used as the intro music for the video, as the band warmed up.
 * In Splatune, Splattack! (Jam Session) fades out, unlike the file in the game, which cuts out abruptly.
 * What appears to be the band shouting Squid Squad! can be heard throughout the song, such as at the 5 second mark.
 * The Splattack! (Octo) remix resembles a corrupted version of the original, paralleling how Tartar has corrupted Agent 3's mind. It could also represent the corruption of Dedf1sh's from being sanitized, and losing her free will.
 * The song sampling DJ Octavio's I Am Octavio makes sense considering that Dedf1sh is an Octoling that served under Octavio.
 * With the purchase of DLC, players can play Splattack! (E3 2014) in Daigasso! Band Brothers P. In April 2016, Splattack! (Jam Session) was also added.

Etymology
Splattack! is a portmanteau of Splat and attack.