This death threat occurred on the wrong planet IRC chatroom in December 2015. I was in Amman, Jordan at the time. It is a fact that JTRIG which is part of GCHQ does infiltrate forums as related by the following article.
I somehow don’t see that this is a prank as it is unusually convincing. Note my views in relation to the NSA have changed since that time, particularly given the fact that GCHQ and the NSA are the same organisation.