When you've got a clogged artery, your options are usually few and risky: anti-clotting drugs or surgery to unblock the clot or reroute blood flow past the blockage. But researchers in China have figured out how to use a laser to clog and then clear a blocked blood vessel in a live mouse, without surgery. This is the first time scientists have been able to externally manipulate cells inside a living animal, and it could lead to a safer way to unclog arteries in the future.