I added a small skeleton army to my bksor pro. I didn't care for the plastics in the back corners and wanted to do something that enhanced the backglass are and theme overall. The idea kept evolving as I found what things were available to me. I was able to make the mod a little interactive with 4 ground breaker bobble head skeletons that I added florescent green eye jewels to and then lit each one with an added comet purple passion bulb. The purple does throw out some UV and the little jewel eyes really glow and all the heads bob. I also added green led eyes to a full body skeleton and a half skull. Things happen to work out that I was able to modify the full body skeletons sword arm move upward as the ball exits the ramp. Here's some short videos and pics. Its the little things in life.

... and the bobble heads

Heres some pics but they never do modding justice!

full on (resized).jpg

sk on lft (resized).jpg

sk on rt (resized).jpg

some with the game off.

full off (resized).jpg

left off (resized).jpg

sk right off (resized).jpg

Here is the one I used. I see a couple of different arm positions as well. They are cheap enough, I may have to order a couple
ebay.com link: Small Buried Bobblehead Skeleton 2 Resin Figurine New Pose A

Here is a link to the figure I used on the ramp. He is a 1994 Skeleton Warrior "Baron Dark." All of the exterior stuff comes right off and you can get him down to just the skeleton. The sword I used for him came from a GOT Ned Stark figure. I did have to super glue all the joints except for his right arm which I had to work to get to swivel easily. I added a rod and a nylon washer on the back for the ball to strike and then led eyes. It took a little messing with but overall wasn't too hard.
ebay.com link: Vintage Skeleton Warriors Baron Dark Action Figure 1994 Playmates GREAT Cond