a large lump of rock that is heading for a planet
Halley's Comet is most probably a collection of ice, dust and rocks; a "dirty snowball" may be the most apt description. I'm not sure that "land" would fit the description.
Need a detalied description of all markings to answer.
No. That description most closely matches a comet.
That description fits a comet. Comets are made up of ice, dust, and rock, and they have long, elliptical orbits around the Sun.
That sounds like the description of a comet. However, please note that comets ONLY have a tail when they are close to the Sun. During most of their orbit, they are too far away from the Sun to have a tail.
a comet/meteorite
It is a comet.
That sketchy description could be applied to a planet, a satellite, a moon, an asteroid, a comet, a meteoroid, or even an electron.
This description matches that of a comet. Comets are composed of ice, rock, dust, and frozen gases, and form a glowing coma and tail when they approach the Sun due to the heating and outgassing of these volatile components.
Halley's Comet
The comet's tail is in front of the comet, not after
=The reindeer who's name is also the name of a kitchen cleanser is COMET=