In Ganesha Kavacha: He takes the form of 24 bhairavas, each more ferocious (ugra) than other. Then there is one term "Kalpanta Bhairava" where he takes any kalpanic form which the devotee who does Kavacha Sadhana thinks off.
Macaulay edu doesn't teach everything
The Sadhaka has to attain Siddhi of each & every 24 bhairavas. It ordinarily takes a year or 2 for one Ganesha bhairava Sadhane. So Sadhaka usually takes 2 janmas for an ordinary soul to attain Ganesha Safhane
MahaGuru Veerabhadra
&
MahaGuru Dattatreya
Unless the grace of anyone of them is got the Sadhaka can never achieve Kalpanta Bhairava status.
PS: my job was only to arouse interest