Detachable arm in Gamera vs. Viras
My favourite moment from Gamera vs. Viras is when the heroic child-stars of the film attempt to lasso an alien, which leads to an Nobuhiko Obayashi-esque airborne arm detachment.
Zigra (ジグラ Jigura)
Zigra lacks the flat out weirdness of Guiron, the brutish panache of Gyaos, and the creepiness of Jiger, but he is still a fun foe. Zigra's convoluted scheme involves kidnapping a sexy spacewoman from the moon, interrupting radio programs with verbal threats, and crowning himself King of the Sea.
Guiron (ギロン Giron)
Goddamn. I love Guiron. He should have got his own spin-off movie. Although it would probably just be torture porn of him chopping up Space Gyaos.
Daimajin (大魔神)
Daimajin is nothing like any other giant monster featured in the Menagerie thus far. Just looking at his physical appearance, it's clear this guy won't be showing up in an episode of Ultraman.