sphinctasaurous 

When the anus protrudes out of its realm and becomes it's own entity as shown in the video cake farts.

I watched cake farts and saw the sphinctasaurous.

sphinctasaurous by RhinoBC December 20, 2018

sphincasaurus 

a prehistoric ass monster that will eventually come to reclaim earth in 2010.

the sphincasaurus will reclaim what is ritefully his and prey that you aren't alive when he does.

sphincasaurus by carlos montaluchayani September 23, 2003

sphinctosaurus rex 

1. The biological term used for the species renowned for its ability to squeeze objects of all shapes and sizes into and out of its anal passage.

2. One who is extremenly anal-retentive.

3. The tightest orifice on the body.

4. The most potent and deadly of all the assholes.

Wow! I thought I could shot a ping-pong ball far until I saw sphinctosaurus rex.

I wish he would lighten up -- he is such a sphinctosaurus rex!

I tried to slip it in to his sphinctosaurus rex, but there was not enought santorum to make it happen.

sphinctosaurus rex by Stanky May 1, 2006