For Mrs. E.V. Sale of Te Ngaere, New Zealand, what happened in her living room during a thunderstorm was like a scene from a Steven Spielberg movie. Lightning struck nearby. Then a flow of light came in under the door. It settled in a blob beside some metal tools on the floor. ''Arms'' flowed out of the blob, weaved between the tools, then contracted only to be extended again. Suddenly the blob drew in the ''arms'' and disappeared under the door. The episode lasted about 15 seconds. There was no sound or odor.
Such is the latest report of a close encounter with a phenomenon that has awed observers for millenniums and baffled scientists for centuries - ball lightning.
The phenomenon is so weird and has resisted explanation so successfully that scientists have traditionally dismissed reports of it as old wives' tales. But an accumulation of reliable accounts, such as that of Mrs. Sale, has convinced many scientists over the past 20 years that they should take ball lightning seriously.
In reporting their investigation of Mrs. Sale's experience recently in Nature magazine, physicists P.W. Burbidge and D.J. Robertson of the University of Auckland emphasize their confidence in her account of what happened late in the evening of Sept. 8, 1981. ''Mrs. Sale,'' they say, ''is an amateur astronomer, and impressed us as a reliable observer.''
But believing in the phenomena is not the same as understanding it. ''No firm conclusions as to the nature of the body seem possible,'' the two physicists say.
They speculate that it may have been an electromagnetic phenomenon involving a mass of air and perhaps other lightning-created gases in which small loops of electric current or some other effect behaved as tiny magnets.
They suggest this would be consistent with the blob's motion. It seemed to be guided by the local geomagnetic field as well as by air drafts.
Martin A. Uman of the electrical engineering department at the University of Florida calls this ''far-fetched.'' However, assessing the Burbidge and Robertson report in Nature, he emphasizes that their ''observations are of considerable interest.''
He explains: ''Reports of ball lightning can be found in both ancient and modern literature, and the similarity in described size, color, smell, duration, sound at demise, and physical damage lends overwhelming support to the view that ball lightning is a real phenomenon . . .''
A typical lightning ball is round or oval. Mrs. Sale's flat glob was unusual in this respect. Sizes range from roughly that of a marble to that of a basketball. The ball glows, lasts a few seconds, and may disappear in an explosion. It can be dangerous and burn objects.
Such balls have entered buildings and aircraft - singeing a pilot's eyebrows in one case. They have been seen by scientists, including meteorologists, as well as by laymen. They have even been implicated in explosions of trucks and tankers that carry petroleum products.
For example, in 1976, I. Ginsburgh and W.L. Bulkley of the Amoco Oil Research Department reported eight such incidents. Typically, what was described as ''a ball of light'' moved across the deck of a ship or entered a transport truck's tank just before the explosion.
Physicist Paul Davies of the University of Newcastle-upon-Tyne, England, has summed up the situation by saying, ''It's all very scary, and one wishes the theorists would do a better job in getting to the bottom of it.''
In this respect, the situation with ball lightning seems to be just the opposite of that with flying saucers. Well over 90 percent of saucer reports are eventually explained as well understood phenonmena, perhaps seen under unusual conditions. Only a few percent are baffling, mainly because investigators don't have enough information to go on.
With ball lightning, on the other hand, many scientists now concede its reality. But so far, they find it to be incomprehensible.