Thanks Detlef and Erik. Yes there is certainly some resemblance to a rattan knife as used in Mainland SE Asia. I think kino's example is a variant of thjat style of knife.
My main thought was that this odd knife is another
pu erh knife used for cutting and splitting a
pu erh tea cake. The blade to cut the cake and the spike to pry off the desired amount of tea leaves from the compacted mass.
You may recall I had
another "what'sit" a few months ago that turned out to be a
pu erh knife.
BTW, I did not win this knife at auction.