CC Madhya 3.97

tore nimantraṇa kari’ pāinu tāra phala
tora jāti-kula nāhi, sahaje pāgala
tore — You; nimantraṇa — invitation; kari’ — making; pāinu — I have gotten in return; tāra — of that; phala — the result; tora — Your; jāti-kula nāhi — there is no indication of Your caste and family; sahaje — by nature; pāgala — You are a madman.
Advaita Ācārya jokingly said, “My dear Nityānanda, I invited You, and indeed I have received the results. You have no fixed caste or dynasty. By nature You are a madman.

The words sahaje pāgala (“by nature a madman”) indicate that Nityānanda Prabhu was transcendentally situated on the paramahaṁsa stage. Because He always remembered Rādhā-Kṛṣṇa and Their service, this was transcendental madness. Śrī Advaita Ācārya was pointing out this fact.