  We present a chemodynamical analysis of 11,562 metal-rich, high-eccentricity
halo-like main-sequence (MS) stars, which has been referred to as the Splash or
Splashed Disk, selected from Sloan Digital Sky Survey (SDSS) and Large Sky Area
Multi-Object Fiber Spectroscopic Telescope (LAMOST). When divided into two
groups, a low-[$\alpha$/Fe] population (LAP) and a high-[$\alpha$/Fe]
population (HAP), based on kinematics and chemistry, we find that they exhibit
very distinct properties, indicative of different origins. From a detailed
analysis of their orbital inclinations, we suggest that the HAP arises from a
large fraction (~ 90%) of heated disk stars and a small fraction (~ 10%) of in
situ stars from a starburst population, likely induced by interaction of the
Milky Way with Gaia Sausage/Enceladus (GSE) or other early merger. The LAP
comprises about half accreted stars from the GSE and half formed by the
GSE-induced starburst. Our findings further imply that the Splash stars in our
sample originated from at least three different mechanisms - accretion, disk
heating, and a merger induced starburst.
