I assume this is the source of the info?
https://starwarsaficionado.blogspot.com/2016/10/deleted-scene-enter-lightman.html
Some more sources:
https://www.youtube.com/watch?v=KyjuHeVJcI4
From this site, there’s some more discussion.
I wonder where aficionado got his info, since his is the only source I can find that suggests this creature had an entire scene devoted to him. Maybe you could email him?
JEDIT: Also interesting to note, these two images show very different costumes. The first one appears to be intended to be placed on the actor’s back, and the second one appears to be on his front, and there are different patterns of lights on each costume.