Uma ThurmanOumuamua was an alien probe.
Just as with Einstein's metaphor of the elevator in which the experience of gravity is indistinguishable from acceleration — and indeed, gravity is an acceleration — our relative position in spacetime with regard to the outer edges of the expanding universe is indistinguishable from being inside the event horizon of a black hole — in both cases, we cannot look beyond the event horizon. Inside the event horizon of a black hole, time becomes a spatial dimension, and this appears to be the same near the edges of the expanding universe.
If it morphs, then that's a solid indication that the object being observed is only the intersection of a higher-dimensional object with our "3+1" spacetime. And considering that we're with the utmost certainty talking of vessels made up of tangible matter — and thus, particles with a rest mass — which can travel interstellar distances in a non-relativistic way, there is no other option than that there would be some interdimensional factor involved.
Nothing with a rest mass can even attain the speed of light, because it would require an infinite amount of energy over a finite time of acceleration, or a finite amount of energy over an infinite time of acceleration. But even then still, if that were possible, then there's also the fact that anything made of matter and attempting to surpass the speed of light by relativistic means would by definition disintegrate as a result of the fact that the forces holding atoms and molecules together work at the speed of light. In addition to that, there would as such also not be any possibility for the pilot(s) to control the vessel by way of either electronics or optics, because they too would only work at the speed of light.
As such, there are only a few ways that anything could be traveling at a velocity perceived to be faster than the speed of light — "perceived" in the sense that the object would be traversing a certain distance in less time than it would take at the speed of light in a vacuum — and all of them involve higher-dimensional physics, i.e. ...:
- warping spacetime as theorized by Miguel Alcubierre;
- a shortcut between two points in spacetime by way of a tunnel that itself runs through a higher-dimensional hyperspace — i.e. a wormhole, also known as an Einstein-Rosen bridge;
- quantum teleportation;
- if brane theory — a variant of string theory — is correct, shifting from one brane onto another, which is in fact analogous to the wormhole in that it's a shortcut and that it requires a hyperdimensional hyperspace.