We got the chance to play around with Marvin's Amazing Magic Pens, which change color when you use the magic pen against them!
Marvin's Magic 30 Amazing Magic Changing Pens
Marvin's Amazing Magic Pens (25 Pack) – Marvin's Magic Worldwide
Marvin's Magic - Amazing Magic Pens - Colour Changing Magic
Coloring with Marvin's Amazing Magic Pens ⋆ Jupiter & Dann
Marvin's Magic Rainbow Colouring Fun – Marvin's Magic Worldwide
Colouring Book and Sketch Pad – Marvin's Magic Worldwide
Coloring with Marvin's Amazing Magic Pens ⋆ Jupiter & Dann
Marvin's Amazing Magic Pens 20 pc - Circle of Knowledge
Marvin's Magic - Amazing Magic Pens - Colour Changing Magic
Marvin's Magic - Original x 20 Amazing Magic Pens - Color Changing
Marvin's Amazing Magic Pens 20 pc - Circle of Knowledge
Coloring with Marvin's Amazing Magic Pens ⋆ Jupiter & Dann
Marvin's Magic 30 Amazing Magic Changing Pens
Marvin's Amazing Magic Pens (2 x 25 Pack) – Marvin's Magic Worldwide