Nightmare Fuel: Apparently she's not the only person whose body moves like that, and while some find the flexibility super awesome, it creeps the hell out of others.
Sampled Up: From Jerry Rivera's "Amores Como El Nuestro". They're different genres and markets, so most people not knowing the original won't be aware in the slightest.
Actually a remake of a Wyclef Jean song called "Dance Like This", which sampled Rivera's.
See Music page for the comprehensive notes on what came from where.