No natural defrost

What strange science-fiction-ish transformation is taking place in the pond?

Strangely shaped ice covers the creeping jenny.

Slowly the sides of the waterfall are being frozen under a thick layer of ice.

Rocks and leaves show through the clear cover of ice, that then cascades down to the stream in chunks like ice cubes.

In fact, my freezer used to look like this before we got the new refrigerator.