This backpack school bag has a special effect!
The design is lenticular! That means that depending on the angle you see the backpack at, the Sonic art here will shift between poses and look like it's moving. The design is covered in tiny ridges of clear plastic that effects how the design is seen & from what angle. This is difficult to photograph (of course) but you can sort of see it going on there if you look below his pointing-away glove cuff, and above his shoes.
Lenticular stuff is neat, IF you can keep it nice & from getting scratched or scuffed up. That means no throwing the bag or banging it against anything. This bag is probably better for home use than school, because of the cool effect. It should be a standard size bag, but where is it sold? This appears in 2017 at Amazon, but only sometimes.