This is a delicious ra-yu (spicy sesame chili oil). You can make it easily at home! (This is not for chunky ra-yu.)
Ra-yu is expensive if you buy it, but the homemade version is delicious and inexpensive!
When you pour the hot oil on the chili pepper, be sure the exhaust fan is running. (Otherwise it may make you cough or your eyes tear up.)
Enjoy Japanese food around the world.