The paper reports the discovery of a long-period radio transient, ASKAP J193505.1+214841.0 (ASKAP J1935+2148), with a period of 53.8 minutes. This source exhibits three distinct emission states: a bright pulse state with highly linearly polarized pulses, a weak pulse state with highly circularly polarized pulses, and a quiescent state with no pulses. The observations suggest physical changes in the emission region, with the quiescent state interspersed between the other two states. The source's radio properties challenge current understanding of neutron-star emission and evolution. ASKAP J1935+2148 was discovered serendipitously during a target-of-opportunity observation of a gamma-ray burst using the Australian Square Kilometre Array Pathfinder (ASKAP) telescope. Follow-up observations with the MeerKAT radio interferometer confirmed the source's properties and timing solution. The source's period and emission characteristics are consistent with other known long-period sources but show similarities to mode-switching pulsars. The authors discuss possible scenarios for the observed emission states, including the involvement of different physical processes and the potential for a neutron star or magnetar origin. The paper also explores the implications for the evolution of neutron stars and the possibility of a new subclass of magnetars with low X-ray luminosities.The paper reports the discovery of a long-period radio transient, ASKAP J193505.1+214841.0 (ASKAP J1935+2148), with a period of 53.8 minutes. This source exhibits three distinct emission states: a bright pulse state with highly linearly polarized pulses, a weak pulse state with highly circularly polarized pulses, and a quiescent state with no pulses. The observations suggest physical changes in the emission region, with the quiescent state interspersed between the other two states. The source's radio properties challenge current understanding of neutron-star emission and evolution. ASKAP J1935+2148 was discovered serendipitously during a target-of-opportunity observation of a gamma-ray burst using the Australian Square Kilometre Array Pathfinder (ASKAP) telescope. Follow-up observations with the MeerKAT radio interferometer confirmed the source's properties and timing solution. The source's period and emission characteristics are consistent with other known long-period sources but show similarities to mode-switching pulsars. The authors discuss possible scenarios for the observed emission states, including the involvement of different physical processes and the potential for a neutron star or magnetar origin. The paper also explores the implications for the evolution of neutron stars and the possibility of a new subclass of magnetars with low X-ray luminosities.