Shaders can be applied while observing the mob with your own vision and freely switch between them

The new command allows you to gain the vision of a spider creeper or enderman. But if you use this command to take, for example, the creeper's vision and then inhabit the enderman in spectator mode, then you can switch between your own vision and the enderman's vision with a single keystroke. How to reproduce:

1. If you have post-effects applied, then clear them with this command: /posteffect clear @s

2. Summon an enderman without AI to make it easier with this command: /summon minecraft:enderman ~ ~ ~ {NoAI:1}

3. Get the creeper's eyesight with this command: /posteffect add @s minecraft:creeper

4. Switch to Spectator mode and inhabit the enderman.

5. You will see everything with the enderman's vision and now press the shader switch key.

6. You can freely switch between your vision and the mob's vision.

As it should be: shaders cannot be superimposed on each other. If you command a mob's eyesight, then if you inhabit another one, you will not be able to get his eyesight.