The third (fourth and fifth) parts in each pack are two scimitar swords and a mount bracket for Mega Cheetor.  The post on the bracket inserts into his um, er, screw hole "butt!"  And the holes in the part are to accommodate the posts on the sword handles. 

We individually hand painted each and every sword using super durable, scratch resistant paints (and admit that the paint job on some isn't absolutely perfect, but pretty darn close).

YES, the swords can hook together to form the wing glider and YES, the swords can hook together to form the boomerang.  To accomplish this, we designed the bumpy green sword handle with a post and a cylindrical hole of the same diameter so the swords can join however you want them to!

In addition, these posts on each sword handle are the same diameter as the post on the toy's tail/"sword" so they insert and fit nicely into the hand of the bot.

The only "catch" if you want to call it that, is that these swords are very sharp, hard and pointy!  Therefore, we labeled all over the packaging that this pack is "FOR COLLECTORS, 18 AND OVER"  We also state these parts were "...not designed with child safety standards in mind so they may be hazardous to children." 

But they look awesome and frankly I love the fact that they're unlike anything made by "big toy companies" concerned w/ child safety standards!  Again, they're "for adult collectors only".

Please note that these swords are designed to with cylindrical posts on each handle.  The posts are designed to fit into the holes in Cheetor's hand.  The first mega Cheetor toy I bought came with hands that each had holes in them for the tail/"sword" to fit into.  We've come to understand that most Mega Cheetor toys now include two different hands.  One has the hole the other hand does not.  In this situation, there are several options to make the sword 'stick' in both of Cheetor's hands.
1.) Using a power drill and a correctly sized bit, (& w/ parental supervision, if necessary!) drill yourself a very small (correctly sized) hole in the other hand to accommodate the sword post.  Try drilling the hole into a piece of scrap wood to make first to make sure the hole is the correct size.
2.) buy a second Mega Cheetor, and swap the holed hand with the non-holed hand.  The parts pop on and off quite easily and you'll end one Cheetor w/ two 'holey' hands.
3.) Without using the post on the sword handle, and using a lot of care, you can balance the sword inside the fingers of cheetor's non-hole hand.  It's finicky, but it will stay if you work at it.
If you have any additional questions at all about this, e-mail Perceptor@unicron.com.  We're happy to help!