AIW2 has Hunter Waves which are waves that join the Threat Fleet directly. Cross Planet Waves are waves that spawn at a nearby warp gate then travel through normal space to attaack you. In principle this is simlar to an Exogalatic Strikeforce, but Exos are much much scarier.
I do like the notion of having a cross planet wave not even tell you which planet it will attack though.
I don't want to tell the player which warp gate is in use because destroying the Warp Gate will cancel the incoming wave in AIW2, so Wave Cancellation is a strategy some players use.
Thinking about this more - what's wrong with destroying the warp gate to cancel the Cross Planet Wave? If it's not overpowered for cancelling normal waves, it shouldn't be overpowered for CPWs either. According to Ovalcircle1, the AI gets more budget for other kinds of attack whenever a wave is cancelled - if you like, you could give it an even bigger boost for cancelled CPWs.
