PGC 21338 is a galaxy in Puppis. This is a crop of the field containing CG4, a well known cometary globule whose appearance resembles an open mouth that appears to be “eating” this galaxy.  Of course, CG4 is a denizen of the Milky Way, while PGC 21338 is over 100 million light years away. Here is the larger field for comparison.

Technical details as follows:

RCOS 16″ @ f/11.3; Apogee U9; Planewave 200HR; LRGB with 8 hours Lum, 8 hours Red, 3 hours Green and 4 hours Blue; processed with Maxim, Registar, Neat Image, Photoshop, and PixInsight; SSRO @ CTIO, Chile; data acquired in January 2012.