Note the qualifiers. This happened 70,000 years ago and the star got no closer than 7.5 trillion kilometres. But still it's pretty impressive.
Based on a paper published in Astrophysical Journal Letters, astronomers now have evidence that another star passed within our solar system in the relatively recent past. The star is a red dwarf, called Scholz's star (an is currently about 20 light years away), passed through the outer reaches of the Solar System, within the Oort Cloud (if that actually exists). Further the red dwarf was accompanied by at least one other object, a brown dwarf (a gas giant that is just too small to have ignited conventional stellar fusion). And possibly by other planets.
The exact effects of the star's passage are unknown but it may have perturbed the orbits of the comets believes to orbit out there on the fringes of the solar system. Possibly swapping material with out solar system.
This also opens up numerous gaming possibilities, from alien objects (even entire planets) left in the outer solar system, to potential alien visits to Earth. Possibly including some relevance to the Toba Catastrophe theory (wiki). This posits that the enormous eruption of a volcano, located at what's now Lake Toba in Sumatra, had a huge effect on the Earth, even triggering the last ice age.