So I've gathered all the parts to build the DCUC Anti-Monitor. Unfortunately, the upper torso is missing the correct pieces to fit the left arm peg. The other side has a hexagon-like hole, but the left side is just a huge opening. Obviously, this doesn't hold the arm! What can I do to get the arm to stick? Would you suggest super-glueing the arm in, or putting something in the hole for the peg to fit in to?

Orion Man, I had a similar issue happen with my Wave 14 Ultra-Humanite upper torso. Unfortunately the best option is just getting a new piece. Supergluing the arm in place might backfire and limit the arm's mobility in the upper torso socket. I tried making my own adaptor for the peg out of styrene and it never stayed in properly.

You could try to trade for the upper torso in the AFI Swap Meet section once you get enough posts or buy a new one from Ebay. If you live in an area that still has the Star Sapphire Wonder Woman (figure that the Anti-Monitor upper torso came with) hanging on the pegs, you could buy a replacement (especially if it is on clearance at Target). Amazon also has the Star Sapphire Wonder Woman for $7.79 as I write this post (Free shipping with Amazon Prime or purchases over $25). Just don't be one of those individuals who returns a figure to a store without the CNC piece.

I just ordered it! Thank you so much for telling me it was on there!