Ice cube tails

Here’s one for you. Does anyone know what causes the little upward " tail " to form on an ice cube ? My theory is that the vibration of the refrigerator compressor sets up a wave motion in the water as it freezes.

Thx, Dave

I thought it was due to a cube freezing from the edge in, leaving a small hole in the center, and the water oozing out as the ice expanded. Only works if the other five sides have frozen first, which is plausible in an ice cube tray, as the plastic has a larger heat capacity than the air. Also probably requires the proper rate of freezing.

The mystery of Spikecicles is a recurrent theme here at the SDMB. I don’t think we’ve ever come up with a definitive explanation, but bbeaty provides some experimental constraints on their formation in this thread:
Spikecicles (reprise)
-Welcome to the SDMB dave664!

The good word from Ken Libbrecht at CalTech: here