I'm sure its come up here before, but...

[The Top Crusader]

[MouthForWar]

[Benjamin Haines]

Removing the laser was a post-production decision. There is that one scene in Godzilla vs. Gigan where Gigan kicks a rock at Anguirus, who then passes it to Godzilla, who then volleys it back at Gigan's head. Then King Ghidorah blasts his gravity beam at Godzilla and Anguirus from behind. After the rock hits Gigan's head, the little laser cannon on his forehead flashes because they had meant to animate his laser in there. The smoke and debris that arise around Anguirus and Godzilla's feet was supposed to be from Gigan's laser, which is why Gigan proceeds to do a happy little jig after that in the film. Somebody in a position of power on the production (maybe Tanaka) supposedly felt that a head laser would be better suited for a human deity character (or something to that effect) and that it wouldn't be appropriate to give that to Gigan, so it was removed and they animated Ghidorah's beam into the scene instead. Never mind the fact that they gave an ocular laser beam to a walking pile of "OH GODZILLA! WHAT TERRIBLE LANGUAGE!" a year prior.

[The Top Crusader]

Interesting, I don't think in the... 7 or so? years I've been on Monster Zero I've ever seen an explanation.

You'd think they'd have airbrushed it out of their promotional art or whatever ended up on the VHS cover, though... But then again Toho of the 70's wasn't always the best about things like that.

[Custer]

[The Top Crusader]

Ha, good point.