Molly & Babyface
Look at Molly. No, look again. Her face model is the same one used for Sid’s creepy mutated toy with name “Babyface.” A few tweaks were made, but the two look so much a like when you truly study it.
The voices of the little green aliens would usually be created with some sort of sound tools, but the creators of the film went old school. The voice actors inhaled helium before saying some of the infamous lines like “The Clawwwww.”