  We report on the tornado-like evolution of a quiescent prominence on 2014
November 1. The eastern section of the prominence first rose slowly
transforming into an arch-shaped structure as high as ~150 Mm above the limb;
the arch then writhed moderately in a left-handed sense, while the originally
dark prominence material became in emission in the Fe IX 171~{\AA} passband,
and a braided structure appeared at the eastern edge of the warped arch. The
unraveling of the braided structure was associated with a transient brightening
in EUV and apparently contributed to the formation of a curtain-like structure
(CLS). The CLS consisted of myriads of thread-like loops rotating
counterclockwise about the vertical if viewed from above. Heated prominence
material was observed to slide along these loops and land outside the filament
channel. The tornado was eventually disintegrated and the remaining material
flew along a left-handed helical path of approximately a full turn, as
corroborated through stereoscopic reconstruction, into the cavity of the
stable, western section of the prominence. We suggest that the tornado-like
evolution of the prominence was governed by the helical kink instability, and
that the CLS formed through magnetic reconnections between the prominence field
and the overlying coronal field.
