Godzilla is a variable star in the Sunburst galaxy at redshift z = 2.37 (or 10.9 billion light years from Earth), observed through the gravitational lens PSZ1 G311.65-18.48.

[1][3] This is possible because the star is believed to be undergoing an episode of temporary increased luminosity that has lasted at least seven years, combined with an estimated magnification of at least a factor of 2000.

Godzilla is believed to be going through an episode similar to the Great Eruption of Eta Carinae in the 19th century, during which the star was likely among the brightest in the universe at about 50 million L☉.

[5] A recent work[6] showed that Godzilla's source-frame ultraviolet light and nebular emission lines as measured by MUSE and X-shooter at the Very Large Telescope (VLT) can be quantitatively explained as that of a star cluster 4-6 Myr after formation and weighing millions of solar masses, magnified by a factor between about 500 and 2000.

Based on the non-detection of flux time variability, which should be induced by intracluster microlensing effects but would be diluted if the source consists of many stars,[7] the study suggests that Godzilla's magnification factor is lower than previously thought, in the range of hundreds.