Makibishi are little pointy metal things that people used to use to stop bad guys from chasing them. You might see them in old movies or cartoons when the good guys are running away from bad guys and they throw something that looks like tacks on the ground.
Makibishi are kind of like really small ninja weapons. They were used in Japan a long time ago by ninjas to stop their enemies from following them. Ninjas would scatter a bunch of these metal spikes on the ground as they ran away, and if their enemies tried to follow them, they would step on the metal spikes and get hurt.
These spikes were made of metal and had four points. When you throw them on the ground, they can land with one point sticking up, which can hurt someone if they step on it. The word "makibishi" means "scattered caltrops" in Japanese, and they were actually used by the military back in the old days as well.
So, in summary, makibishi are little metal spikes that were used by ninjas and soldiers in Japan a long time ago to stop enemies from following them.