I don't believe the kids did anything (unless they spilled liquid on the keyboard). I've read some threads where additional characters or different characters appear when certain keys are pressed. I think you've got a defective keyboard and recommend exchanging your laptop for a new unit if you are still within your retailer's exchange/return period.
Don't let them talk you into an RMA.

I would attempt an ASUS Factoty Restore as a last attempt.at a software fix. Press F9 at the ASUS splash screen and choose Option 1 to restore Windows to the 1st partition. Be sure to backup any important files on that partition as it will be completely overwritten.

Looks pretty much like pork byproduct to me...