Dark Pulsar

Dark Pulsars are one of the rare situations where normal space naturally impacts the Hypersea. Not as well known as the Lux Aeterna, but far more useful, a dark pulsar is a pulsar which occasionally emits a so-called 'dark pulse', which is so intense that it echoes into hyperspace.
The dark pulse causes Relativity to drop and Tranquility to improve, which means for a short while the Hypersea becomes easier to navigate. This means these rather-regular occurrences basically create a temporary shortcut, which in some cases can cut entire weeks off your traveltime. Fuel and time are both expensive, so dark pulses are quite popular with merchants.
A downside is that dark pulses tend to disrupt Hyperdrives, so one had best wait far enough away to not accidentally get hit. This also makes guarding the shortcuts harder, as a dark pulse can wreak havoc on a Hypersea Base or Starship. With shortcuts harder to defend, they have occasionally been used by malicious forces, through guerrilla warfare or pincer movements.

The Sciencey Bits

Pulsars are extremely constant and fast, generally emitting fast enough that they are effectively sending out a radio signal. But some of them build up a tension that releases at near-constant intervals, ranging from days to years. This tension comes out as a special solar flare which combines with the normal pulse to cause a faster-than-light wave oscillating through Hyperspace. For some pulsars, the direction is always almost the same, while for others it is more random.
The wave interacts with dark matter and dark energy on its way. As the Hypersea originates from interactions of hyperspace with dark matter in real space, this oscillating wave thus manages to calm down hyperspace to a point that ships can temporarily pass more easily. For a while this will slowly go back to a normal state, until suddenly the collapse accelerates. Fortunately for starships, this collapse is detectable in advance so only rarely does a ship end up crashing out of hyperspace.