The colour 'Red' ceases to exist as it is swallowed whole by the cannibalistic colour 'Gold'.

The Toa are in immense pain from having multiple surgeries to add and remove gears into their hips and backs, and from having their oddly transparent brainstalks exposed from behind.

Something gets horribly mutated by hordika venom/pit mutagen/desire for power/uncontrollable masks/plot device.

The Toa Mahri remain irrelevant, being G1 characters and thus having nothing to do with the G2 story.

Tahu seethes red when he learns that he is all-gold, thus defeating the plague of Gold, and renounces the Golden Armour entirely because it doesn't exist in G2 and there are no Rahkshi to killify.

The Skull Skeletons return, except this time they're just heads - they're skeletons, they don't need bodies. They become annoying sidekicks to the Toa. Except Skull Scorpio.

Okoto is actually a giant mask on top of a giant robot, whose name is