This is the means by which some of the Far-Right and fringe parties are able to enter government. Under the parliamentary system (which I still think is better than the US model) a party who wins the election without a clear majority must form a coalition government.
It is under the auspices of a coalition that some Right or even Centrist parties can turn to the Far-Right and bring them on board. A few concessions and compromises gets the necessary votes and for the fringe party... they get their foot in the door. Their hope is that name recognition and perhaps a few high profile positive news events will generate more votes in the next election.
Critics of the parliamentary system will point to this practical reality as a point of weakness.
Critics of the US winner-take-all presidential system will counter by arguing that such a system would naturally and even necessarily devolve into a two-party structure. That same structure will unify and circle the wagons to bar all challengers... and that's exactly what has happened. The American Founders weren't thinking in terms of political parties and failed to see that they would necessarily develop and then devolve into the two-party model.
Ironically it is the parliamentary system that is in the end more democratic. I don't say that to champion democracy but instead find it ironic that such a reality does not even remotely fit the perceptions held by most Americans.