Yes, Headstand Pose is called the "King of Asanas" and for good reason!
It's typical at some point for most all yoga students to be tempted by those scary looking yoga inversions. Some yogis may even decide to try them sooner rather than later. After all, inversions do present challenge and they can be very fun once you attain the proper strength. In the meantime, students should approach the more difficult inversions with caution.
Headstand Pose in many cases will be the first inversion that students decide to practice. As mentioned, Headstand is referred to as the "King of Asanas" or "King of Poses". This honor is bestowed on the pose because of all the rich benefits offered by the posture. It should be noted that Shoulder Stand Pose is considered the "Mother of All Poses" and is also known as the sister posture to Headstand.
Sirsasana is the Sanskrit name for this posture. The breakdown for the Sanskrit name is as follows, "Sirsa" meaning "Head", and "Asana" meaning "Pose". Of course, once combined you have the name Head Pose or more commonly Headstand Pose. There are also many different variations of this posture, some offering more challenge and others perhaps a little more simplicity.
There's no doubt that the "King of Asanas" is packed with plenty of challenge, fun, a little fear, and many health benefits. As with all inversions, practice the pose with caution and the help of an instructor if you're a true beginner or brand new to the pose.