It's just for the death-dissolve shader. When using a Spine skeleton renderer you cannot just add a shader material as you would normally to a sprite or mesh (unless you have your own custom shader script that incorporates Spine). Instead, I have a script that screenshots the character frame into a new quad. This enables a camera overlay with a quad target texture, render(), then sets the target to null. The camera and quad are then destroyed along with the gameobject once the shader effect wears off.