Sometimes when throwing an EasterEgg at an animal or infected, it'll play the particle and sound but not capture the entity. I've taken a look at the script for the EasterEgg and it seems like the sound effect and particle effect are only firing on client verification of OnTouch and OnContact, which can cause inconsistencies. The particles and sounds should be verified by the capture state from the server. Chickens and roosters are a good entity to get results of this, since their bounding box is so small.