[Hedgehog Fog]

EFFx,
I have no idea what do you need.
It's can be helpful for complex project (Halloween Mod for example).
This allow to you register new entity class and use this class on your map for example.
This allow you to controll entity remove and clear some data, for example arrays, which binded to entity and store in pev_iuser1 as handlers.
It's remove entities automatically in new round.
It's allows you to make temp entities with life time.
It's allows you to hook pickup events, it's can be usefull if you have a lot of item entities, so you don't need to create forward for each item.