This odd cloud was seen five days ago in the city of Pagadian, located in the Philippine island of Mindanao. It got my attention due to it being so close (~150 nautical miles) to the epicenter of very large earthquake (7.2) earlier today, April 28, 2017.
A rainbow-unicorn cloud was spotted in Pagadian City, Zamboanga Peninsula, Philippines just this April 23, 2017.
The earthquake was today, same general area of Pagadian (upper left in image). Pagadian and General Santos City are about 146 nautical miles apart.
I also found it interesting that one source, the USGS, reported multiple shocks, the first 6 miles deep, then just 1 second later, 26 miles deep. The quake, or something else, was headed down into the earth at 1,200 miles per hour.
By 1:23:21 seconds it was 37 miles down, from which, if the sources are exactly synchronized, we can say the underwater earth-penetrating unicorn had slowed to 330 miles per hour. A few calculations would locate the underground unicorn base camp.
There are more reasonable explanations, like some dumped rocket/jet fuel in the clouds and an ordinary undersea quake coincidentally in the same area a few days later, but it is fun to speculate as to other possibilities.