SAN DIEGO -- One of the newest trends on school campuses is also one of the most dangerous, 10News reported.

It was about noon in the boys' locker room at Kroc Middle School when an eighth-grader brought an airsoft gun to school and aimed it at a seventh-grader.

"He shot one other student, (it) hit him in the arm (and) left a little red welt," said Vice Principal Doug Coffey.

It wasn't a serious injury, but there's zero tolerance on school grounds and punishment is swift.

"You will be suspended five days (and) recommended for expulsion. Even if you touch it (or) bring it for fun. All we want at school is school supplies," said Coffey.

The guns are very realistic. It's not just the act of harming another student, but the one holding the gun is in danger, too, 10News reported.

"There's the kid who brings (a) gun (and) risks being shot by police. There's the kid who gets injured (and) goes home and gets (a) gun and comes back. Third, the kid who's asked to hold a gun as a favor," said Katherine Nakamura, with the San Diego School Board.

About a year ago, Scripps Ranch High School was locked down briefly when a student was reported to have a submachine gun in his backpack. It was an airsoft -- a toy that one boy was going to sell to the other for $150. They were two good students with good records, but they were led away in handcuffs, 10News reported.

That was one of 88 such incidents in the past year. Most lead to expulsion.

The fake guns are easy to acquire. The are sold at many stores and the Internet. 10News is told they have even been sold from the back of an ice cream truck in San Diego.

They are illegal for under anyone under 18 in public places and are dangerous for anyone in the wrong situation.