Get used spawn egg itemstack

[fr3qu3ncy]

How can I get the used ItemStack from SpecialSpawn? I want to do things based on if a mob was spawned by a special spawn egg. I tried adding a CompoundNBT with this hierachy:

EntityTag

- ForgeData

   - MyTag

      - true

to make it merge this data into the persistentData of the entity, but it's always empty.

[fr3qu3ncy]

3 minutes ago, diesieben07 said:

Is this for your entity?

No, it‘s for an entity from another mod

[fr3qu3ncy]

11 minutes ago, diesieben07 said:

Show what you tried with the entity tag.

I tried this.