Koodi Puja, where Koodi meaning Joint, is a significant Joint Puja of two lords conducted only in the Vaikom Mahadevar Temple. This puja is performed after the Arattu of Vaikathappan (Deity of Vaikom temple) at the Udayanapuram Temple. It is a special puja after the Athazha Puja, Sreebeli and Sreebhoothabeli.
During the Koodi Puja, Vaikathappan and Udayanapurathappan (Deity of Udayanapuram Temple) are seated together. The puja is performed by the Tantri of the temple and nobody is allowed other than the Tantri during the occasion. The Puja mantras and the dhyana slokas are so secret. It is believed that the Darshanam of the deities after the Koodi Puja will recover the devotee from all his sins (Sarva Papa Haram), because of the auspicious presence of two lords. This time is a significant moment for Choruoonu (first feeding of babies), Adima Kidathal (making a slave under the Lord), and Thulabharam (Weighing in the balance with articles like sugar, jagary or plantains).
After the pujas inside the shrikovil, Vaikathappan and Udayanapurathappan are brought to the Namaskara Mandapam and placed on two special Peedhams. After the special pujas, the idols are carried on caparisoned elephants accompanied with decorated umbrellas and tunes of devotional musical instruments, to the site of Koodipooja Vilakku. After the Vilakku, the lords depart in a very emotional way. All these functions depict the nobility and greatness of Adhithya Maryada (hospitality).