Over the ages there have been many accounts of ball lightning.
Some accounts from Wikipedia are as follows:
One of the earliest descriptions was
reported during The Great Thunderstorm
at a church in Widecombe-in-the-Moor,
Devon, in England, on 21 October 1638.
Four people died and approximately 60
were injured when, during a severe
storm, an 8-foot (2.4 m) ball of fire
was described as striking and entering
the church, nearly destroying it.
Large stones from the church walls
were hurled into the ground and
through large wooden beams. The ball
of fire allegedly smashed the pews and
many windows, and filled the church
with a foul sulfurous odor and dark,
thick smoke.
The ball of fire reportedly divided
into two segments, one exiting through
a window by smashing it open, the
other disappearing somewhere inside
the church. The explanation at the
time, because of the fire and sulfur
smell, was that the ball of fire was
"the devil" or the "flames of hell".
Later, some blamed the entire incident
on two people who had been playing
cards in the pew during the sermon,
thereby incurring God's wrath.
One without a religious angle:
In 1954 Domokos Tar, a physicist,
observed a lightning strike during a
heavy thunderstorm. A single bush was
flattened in the wind. Some seconds
later a speedy rotating ring
(cylinder) appeared in the shape of a
wreath. The ring was about 5 m away
from the lightning impact point. The
ring's plane was perpendicular to the
ground and in full view of the
observer. The outer/inner diameters
were about 60/30 cm. The ring rotated
quickly about 80 cm above the ground.
It was composed of wet leaves and dirt
and rotated counter clockwise. After
seconds the ring became
self-illuminated turning increasingly
red, then orange, yellow and finally
white. The ring (cylinder) at the
outside was similar to a sparkler. In
spite of the rain, many electrical
high voltage discharges could be seen.
After some seconds , the ring suddenly
disappeared and simultaneously the
Ball Lightning appeared in the middle.
Initially the ball had only one tail
and it rotated in the same direction
as the ring. It was homogenous and
showed no transparency. In the first
moment the ball hovered motionless,
but then began to move forward on the
same line with a constant speed of
about 1m/sec. It was stable and
travelled at the same height in spite
of the heavy rain and strong wind.
After moving about 10 m it suddenly
disappeared without any noise.
There are also videos purporting to be ball lightning available on YouTube and I have heard a hypothesis that this UFO incident could be ball lightning.
So the question remains is ball lightning scientifically verifiable, or is there another explanation for all these events (e.g. meteorites, imaginative stories, video manipulation, etc).