Undertale/Godzilla

Toriel as Godzilla

Flowey as Biollante

Sans and Papyrus as King Ghidorah

Undyne as Rodan

Alphys as Anguirus

Mettaton as Mothra

Napstablook as Mothra Leo

Asgore as SpaceGodzilla

Bratty and Catty as the Shobijin