The Twin Vaif are a pair of Big Moai, and as such, they can spew out miniature Moai toward the player. The US version of Gradius III calls them Mega Monolith. Their weak point is the mouth, and both must be destroyed in order to defeat them.
Unlike the original Vaif arcade boss, which consisted of six Moai facing in odd directions, Twin Vaif has been reduced to only two, keeping the same basic attack as Big Moai. They can now occasionally cause earthquakes, which makes loose rocks to drop from the ceiling. When one of them is killed, an additional earthquake will happen; and even when the final one is eliminated, care must be taken to avoid their final attack, as this can still kill the player.
|Stages||Desert • Bubble Zone • Volcanic Planet • High Speed Dimension • Moai Zone • Cell Planet • Prominence Planet • Plant Planet • Crystal Zone • Boss Rush • Mechanical Base|
|SNES exclusive stages||High Speed Zone • Fortress • Cell|
|Bosses||Goliath • Bubble Eye • Godrei • Big Core MK III • Dogas • Vaif • Twin Vaif (SNES) • Gregol • Wyvern • Vulture Dragon • Choking Weed • Lizard Core • Beacon (SNES) • Tetran • Covered Core • Big Core MK II • Crystal Core • Death MK II • Dellinger Core • Disrupt • Shadow Gear • Shadow Gear MK II (SNES) • Big Core • Golem • Bacterian|
|Enemies||Moai • Jumping Moai • Petit Moai • Rolling Moai • Totem Moai • Mother Moai • Dogas • Flying Moai • Chewing Moai • Big Moai • Clattering • Yoshida • Samoai No. 3 • Captain Moai • Flasher Maoi|
|Bosses||Big Moai • Armored Saint • Vaif • Twin Vaif • Moai Dimension • Alpha/Omega • Dogaltes • Moai Orb • Crystal Moai • Viking Moai • Yoshiko|