Assalaamu alaykum. I want to know about Thul-Khalasah.

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.

Thul-Khalasah was an idol worshipped by some Arab tribes, and it was demolished by the honorable Companion Jareer ibn ʻAbdillaah Al-Bajali at the orders of the Prophet . Jareer ibn ʻAbdillaah said, "There was a house called Thul-Khalasah in the Pre-lslamic Period, and it was also called Al-Kaʻbah Al-Yamaaniyah or Al-Kaʻbah Ash-Shaamiyyah." The Messenger of Allaah said to me, "Will you relieve me from Thul-Khalasah?" So I left for it with 150 cavalrymen from the tribe of Ahmas, and we destroyed it and killed whoever we found near it. Then we came to the Prophet and informed him about it, so he supplicated Allaah for us." [Al-Bukhari and Muslim]

Al-Haafith Ibn Hajar wrote, "Al-Khalasah is a plant with red seeds ... Thul-Khalasah was the name of the house in which the idol was placed, and it was also said that the name of the house was Al-Khalasah and that the idol was known as Thul-Khalasah. Al-Mubarrid narrated that the location of Thul-Khalasah has become a large mosque for a town named Al-ʻAblaat in the lands of Banu Khathʻam tribe." [Fat-h Al-Baari]

Allaah knows best.