Ned Raggett of AllMusic described the track as "surprisingly commercial for the band" and highlighted its "memorable main riff and drumming" as pleasingly listenable; he selected the song as one of his favourites from Pure.

[2] Joseph Schafer of Decibel agreed with Raggett, considering "Mothra" one of Godflesh frontman Justin Broadrick's most accessible songs, but added that "it still sounds like getting crushed by a ton of lead".

[3] Mike Gitter of Spin and RIP Magazine described hearing "Mothra" by writing, "It's as if your whole body is made to serve as a giant ear, as you are beaten upon by a low-level shock wave.

[5] As is the case with most Godflesh songs, "Mothra" was recorded with a drum machine, which, according to Shawn Macomber of Decibel, "really hammers the [Steve] Albini vibe" in allusion to the band Big Black.

Directed by Barry Maguire in 1992, the video was described by the band as "a curious affair that mixed David Lynch-style cinematography and concepts with performance shots of Godflesh in a dodgy-looking disco".