Abstract During some exploratory experiments performed on a centerbody burner it was observed that the sooting behavior of the burner could be altered dramatically without changing the fluid dynamics. One of the interesting operating regimes, in which the flame lifts off and forms a column of soot, was identified when oxygen in the annular flow was sufficiently reduced. More interestingly, within a narrow window of flow conditions, an unusual toroidal flame was observed near the base of the lifted flame. This paper describes the numerical and experimental studies performed for understanding this peculiar toroidal flame tube. A time-dependent, axisymmetric, detailed-chemistry CFD model (UNICORN) is used. Combustion and PAH formation are modeled using Wang–Frenklach mechanism and soot is simulated using a two-equation model of Lindstedt. Calculations have accurately predicted the steady lifted flame that is anchored to the outer edge of the recirculation zone. Lift-off height of the computed flame matched well with that of the experiment. A dynamic lifted flame is then established through periodically oscillating the annular flow. The edge of the lifted flame is found to dance along the outer periphery of the recirculation zone while vortical structures establish downstream of it. However, none of the calculations made with varying flow conditions or perturbations yielded a toroidal-flame structure near the base of the lifted flame. Surprisingly, when time-averaging was performed for the CH-radical distributions of the dancing flame a toroidal flame-like structure, very similar to that observed in the experiment, appeared near the flame base. Based on these calculations and high-speed movies of the experimental flame it is concluded that the observed toroidal flame is an optical illusion created through the natural time-averaging process of the human eye. Detailed structures of the computed oscillating flame are compared with the thermal images of the flame obtained using an infrared camera.