The entity inside will always watching your mouse(always).
The author thinks it would be very interesting to add such an entity display in the FTB Quests.

/give @p entity_display_item:entity_display_item[minecraft:custom_data={DisplayEntityType:"minecraft:pig",DisplayMobScale:1.5f}]
/give @p entity_display_item:entity_display_item[minecraft:custom_data={DisplayEntityType:"minecraft:pig"}]
If you encounter any bugs or have good suggestions, you can provide feedback.