The t-shirt says: "As the child of a white mother and a black father, I got called Zebra and Oreo Cookie in school"
I am not usually politically correct when it comes to race because I feel people need to grow up and not get on their little black horses about every little race related remark or name, but this one goes a little bit to far. I know that few Koreans understands what the shirt says, and I know that quite likely it was not meant as an insult, but still, it is not very nice. It's funny in an evil way, but not nice.
The really scary thing is that this is something children here will likely say to a child of black and white parents. The one boy in my school is naturally darker than the other students, therefore his nickname is "Black". Other students never let a chance go by to point this out to me.