I may have got a bit behind with version control. A lot behind, in fact. Maybe I'll go back and split this sometime - then again, I probably won't. But hey, at least it's here!
Switch to an EnumSet for immunities, both because it's more efficient for this purpose, and because adding immunities to an entity caused a crash, because of improperly attempting to extend an array through the asList wrapper.
Electroblob77