Tingkat

Here's my take on the Tingkat (alas better known under the mistranslated names Tyngkatt and Tenong Cut), a practically unknown Malaysian spirit from the folklore of the Jah Hut tribe, whose members mostly inhabit the State of Pahang nowadays. It spends most of its life in the ground, but comes out of it when it's hot and the sun shines while it rains. Under these circumstances, the Tingkat is able to "possess" people, making them feel that their head is getting heavier, as if something was sitting on it. It is a rather benign member of the Bès (or Hantu), evil spirits associated to various diseases in Jah Hut folklore.
The wood carvings depicting the Tingkat present two spirits, one atop the other ; it could be seen as a pure metaphor about the illness it causes, but thinking that Tingkats always go in pairs remains a possibility.