Ben 10 series is quite popular among kids. The character Ben Tennyson, the witty and funny guy, is popular, well-loved, and the main character in the series. This toy, Ben 10 Ben and Grey Matter, contains a set of two characters - Ben and Grey Matter. Kids would love this ultimate kid superhero, and the alien called Grey Matter The Ben uses his super watch called Omnitrix and helps others. The alien - Grey Matter, is an intellectual and is stronger than it looks.