To imitate the spot I used a Gradient colour. Open the Colour Menu and select the tab Gradient. Set the Gradient to Radial. Select three colours on the colour-slide; black with Alpha percentage of 0, a dark yellow with an Alpha percentage of 30, and another black with Alpha percentage of a 100. Draw a perfectly round circle; use the Shift key, with the Gradient as a fill. To centre the fill in the circle you can use the Transform Fill-tool. (I use this tool a lot to make various colour effects.)
