Ninja Assassin

Ninja Assasin is an even advanced version of Ninja Zombies. This time, the Ninja can multiply into three. Each ninja will move at a different row close to each other. When the Ninja Assassin multiplies, the real ninja will be shuffeled to another lane while the other two are clones. The clones can't be killed unless the original one is killed. When the original one is killed, all thre of them will turn into a puff of smoke.