Exactly at that time, however, Durvasa Muni, the great and powerful mystic, appeared on the scene as an uninvited guest

Expressions researched:
"Exactly at that time, however, Durvāsā Muni, the great and powerful mystic, appeared on the scene as an uninvited guest"

Srimad-Bhagavatam

SB Canto 9

Thereafter, Mahārāja Ambarīṣa satisfied all the guests who arrived at his house, especially the brāhmaṇas. He gave in charity sixty crores of cows whose horns were covered with gold plate and whose hooves were covered with silver plate. All the cows were well decorated with garments and had full milk bags. They were mild-natured, young and beautiful and were accompanied by their calves. After giving these cows, the King first sumptuously fed all the brāhmaṇas, and when they were fully satisfied, he was about to observe the end of Ekādaśī, with their permission, by breaking the fast. Exactly at that time, however, Durvāsā Muni, the great and powerful mystic, appeared on the scene as an uninvited guest.

SB 9.4.33-35, Translation

Thereafter, Mahārāja Ambarīṣa satisfied all the guests who arrived at his house, especially the brāhmaṇas. He gave in charity sixty crores of cows whose horns were covered with gold plate and whose hooves were covered with silver plate. All the cows were well decorated with garments and had full milk bags. They were mild-natured, young and beautiful and were accompanied by their calves. After giving these cows, the King first sumptuously fed all the brāhmaṇas, and when they were fully satisfied, he was about to observe the end of Ekādaśī, with their permission, by breaking the fast. Exactly at that time, however, Durvāsā Muni, the great and powerful mystic, appeared on the scene as an uninvited guest.