  The first spectroscopic observations of cool Mg II loops above the solar limb
observed by NASA's Interface Region Imaging Spectrograph ({\it IRIS};
\cite{IRIS}) are presented. During the observation period IRIS is pointed
off-limb allowing the observation of high-lying loops, which reach over 70~Mm
in height. Low-lying cool loops were observed by the {\it IRIS} slit jaw camera
for the entire 4 hour observing window. There is no evidence of a central
reversal in the line profiles and the Mg II h/k ratio is approximately 2. The
Mg II spectral lines show evidence of complex dynamics in the loops with
Doppler velocities reaching $\pm$ 40 km/s. The complex motions seen indicate
the presence of multiple threads in the loops and separate blobs. Towards the
end of the observing period, a filament eruption occurs that forms the core of
a coronal mass ejection. As the filament erupts, it impacts these high-lying
loops, temporarily impeding these complex flows, most likely due to
compression. This causes the plasma motions in the loops become blue-shifted
and then red-shifted. The plasma motions are seen before the loops themselves
start to oscillate as they reach equilibrium following the impact. The ratio of
the Mg h/k lines also increases following the impact of the filament.
