Watch Monsters, Inc. (2001) HD Full Movie Free on SolarMovie. Watch Monsters, Inc. (2001) online free. In order to power the city, monsters have to scare children so that they scream. However, the childr...In order to power the city, monsters have to scare children so that they scream. However, the children are toxic to the monsters, and after a child gets through, two monsters realize things may not be what they think.