You really can make anything with duct tape.

In the Mantis facebook group, someone brought up the lack of holsters that accommodate a mantis attachment. This is an issue when you are doing drills that require holstering and drawing.  My existing holster for my Mantis is this Ghost Holster, but when the mantis is attached, the holster won't work.

The barrel goes on that little knob on the bottom, and the trigger goes in that slot by the "Gh" part of the logo.  The Mantis is attached on the underside of the rail and prevents the trigger guard from fitting into the slot and locking.

This last year for a family fun activity, Cathi stopped by Walmart and picked up a bunch of roles of different colored duct tape.  She designed an activity where the family would have a duct tape building contest.  You can make whatever you want out of duct tape and any other type of material.  I found some cardboard and measured my CZ Shadow 2 while it has the Mantis attached under the rail.

This worked awesome, and I even fashioned it with a G.  Except when I was done, I realized I had put in the belt slot on the wrong side so that the holster was built as a left side holster.  But it still works, just not as form-fitting as I originally had designed.  But it's tight and keeps the gun in a functionally protected way and stable for doing holster draw / shoot drills.  I would never use this as a real world holster by any means. 

Here is some video of me using the CZ Shadow with the Ghost holster for drawing.  I've only done 2 USPSA matches which were totally fun by the way.  And I'd like to do it again sometime.  But right now ammo is so pricey, that it would have to drop back down to normal for me to justify that expense.