2I/Borisov, originally designated C/2019 Q4, is the first observed rogue comet and the second observed interstellar interloper after ʻOumuamua. It was discovered by the Crimean amateur astronomer and telescope maker Gennadiy Borisov on 29 August 2019 UTC.
2I/Borisov has a heliocentric orbital eccentricity of 3.36 and is not bound to the Sun. From Wikipedia
