Noun (Verbal Noun, Transitive Noun, Countable Noun. Plural: monster shits)
1) (Verbal Noun). The act of defecating particularly large or stubborn feces from the digestive tract via the anus (in this context the feces are usually solid, but sometimes the feces can be semisolid or even liquid and still qualify as a monster shit).
2) (Noun). The feces itself that resulted from the monster shit. To safely qualify as a monster shit the feces must be remarkable in some way, such as having an unusually large mass, density, texture or any other obvious quality which identifies it as a remarkable bowel movement.
Also of note is that some people claim to have laid a monster shit, when in fact it was only an above average bowel movement. The stress of laying above average feces may make the resulting feces seem larger than they are. Applying the valsalva maneuver by holding your breath and "pushing" to force out firm feces can heighten the senses, making your anus hyper sensitive which can give the impression that your shit is larger or more monstrous than it actually is.
1) "I can't talk now Jane, I am taking a monster shit and it requires my complete attention so I will have to call you back"
2) "I wouldn't go to the garden shed for a little while, Bobby got high again and laid a monster shit right on top of your lawn mower"