Minecraft Username: m33crob Brief Description: zombie pigmen and ghasts despawn. Instructions: approach either entity and they will disappear. How many times did you recreate this bug?: lots. Result: they disappear every time. Expected Result: not disappear. Evidence: http://www.ecocitycraft.com/forum/threads/are-pigmen-and-gasts-supose-to-spawn.28785/ I have to suspect that this is an intentional action; but since there haven't been any announcements regarding this, I felt the need to post in this section.
The fact that I spend 85% of my day in the nether and I never see a Ghast, let alone see a Pigman, this will be hard for me to test. But I will head out now, and report my results in an hour or so.
Confirmed, Pigman despawn, not sure about Ghasts. But when I get in a 10 block radius of the Pigmen, they despawn.
