Joska send me photocopies of a UFO sighting he and his wife had while he was living in Brussels (1967). The photocopies were taken from the book A Identifier et le Cas Adamski  by J.G. Dohmen (Guy Dohmen Pub 1972) in which his sighting was mentioned. Joska Soos, being both shaman and artist, was able to observe and describe in detail this strange occurrence. Click on the image below to view the photocopies (text is in French). Below is a translation. The book also displays a couple of his black-and-white art.

Translation (this is an automatic translation with some corrections, of only the part where Joska describes his sighting):

Artistic interpretation of nocturnal phenomenon SCALABLE in SIX PHASES - Brussels 04/29/67.

Another observation is that from the painter JOSKA SOOS....
To return to this " variable geometry" at the end of April 1967 , simultaneously or successively SCHAARBEEK - BRINDISI and airport Melsbroek were registered events variable character . The similarity is striking and goes with a new series of observations recorded in Europe since March , after a lull in June and a recovery in Belgium in early July of phenomena to rank among the most amazing .

SCHAARBEEK - BRINDISI

29-4-67 22 h 40 to 23 h 45 ( Sketch).
Mr. and Mrs. SOOS, from the floor of nº5 , Marshal Foch Avenue, were watching for 45 minutes a strange sight :
Fig. 1: An orange body moves very slowly from NNW to north, a steady rise that will fit in a 20 ° angle. It has the shape of a cigar tilted to the left, as shown in our sketch that reflects the apparent shapes. Duration of this first phase: about 20 minutes.
"Our friend SOOS is a painter, what explains the colorful descriptions he easily remembers. This report was also written down the next day."

Fig. 2: The ellipse doubles but retains its shape. The color remains orange, but gains in transparency and brightness. The two ellipses are keeping themselves in balance with a more pronounced movement at the top the object. The ellipse in the foreground is slightly darker than the one that is partially eclipsed. Phase duration: about 40 seconds.

Fig. 3: The separation increases, while in the center of the two surfaces appear white circles. The two inner faces are connected by two light bars; they are of a bluish gray with green mixed in it. They emit silver and light blue sparks. Slice (or apparent thickness) of these kinds of almost circular wheels, are having the same color than that of the bars. Duration of the 3rd phase a minute.

Fig.4: It all suddenly rears, rocks and turns into one shape again that resembles that of a cigar. The bright spot remains in the center of the orange surface. The outer rim becomes hazy and milky. This length is a quarter of the central thickness of the cigar. This transformation has only lasted a few seconds.

Fig.5: The shape lengthens, flattens and the surface diminishes, while it rises and it seems to move away. At both ends a rotating helix of light forms. These structures are hazy and milky as is the outline of the cigar. At the end of the phase transformation, about 15 minutes, the elongated body had diminished its size to a third of its surface.
Fig.6: A controlled explosion? The object then appears to "explode in silence" in a blinding light emission. This curiously symmetrical dissipation occurs in two distinct phases spread over a period of about 4 minutes:
a) At the forefront and center forms a divergent beam with slanting rays whose enlargement is down. The upper third is green and white. The center, limited, it is also white, but with crimson rays. As for the lower half this is made of a variety of carmine red.
b) Simultaneously, with these rays as a background,  both at the left and at the right rays of blue and crimson appear which creating a shape of a triangle with the top cut off. Directed outwards, the rays converge at a point (cut off) of which the position is perpendicular to a straight imaginary line going to center of the device.

The small binoculars they used did not give any more detail. Because of the cold, the witnesses were going back inside, and when they came out later there was only a vague shape left in the distance...