  Here we present the discovery of three unusual long-term variables found in
the Digital Access to a Sky Century at Harvard (DASCH) project, with ~1
magnitude variations in their lightcurves on ~10-100 yr timescales. They are
all spectroscopically identified as K2III giant stars, probably in the thick
disk. Their lightcurves do not match any previously measured for known types of
variable stars, or any theoretical model reported for red giants, and instead
suggest a new dust formation mechanism or the first direct observation of
"short" timescale evolution-driven variability. More theoretical work on the
lithium flash near the Red Giant Branch (RGB) bump and the helium shell
ignition in the lower Asymptotic Giant Branch (AGB), as well as long term
monitoring of K2III thick disk stars is needed.
