This article lacks a picture, it needs to be added...
"Shuwatch" is an exclamation commonly associated with the Ultraman series, a media franchise created by Tsuburaya Productions.
It is Ultraman's "catchphrase", so to speak.
However, basically, Ultramen don't say "Shuwatch" when about to attack the enemy or shoot a beam at them (in that case, they shout other exclamations such as "Heah!", "Shaa", "Dyuwah", or "Dahh!"). Ultraman shouts this just before defeating a kaiju and flying off the scene.
Then, the reason why this word (?) has become synonymous with Ultraman is that it has become common to parody Ultraman by drawing characters saying it.
- Ultraseven: "Dyuwah!" (デュワッ!)
- Ultraman Taro: "Tooah!" (トァーッ！)
- Ultraman Leo: "Eeyah!" (イヤァー!)
- Ultraman X: "Issah!" (イーッサ!)
- Ultraman Orb: "Orya!" (オウリャ！)
- Ultraman Z: "Kiah!" (キアッ！)
- Ultraman Zero: "Deryah!" (デェリャッ！)