There is a theory in quantum physics that states for every possible outcome of a situation an alternate timeline is created with that outcome. For example, say you're walking up to a banana peal. In the fraction of a second you both step on the peal and step over the peal. So, going into one situation, two realities exited. Actually many more realities then two were created, but I'm just trying to keep it simple.
A common misconception of the Multi-World Theory is that an infinite number of realities comes out of any situation. A common description is; you walk up to the banana peal and instead of stepping over the peal or slipping on it, you sprout a third arm. This does not happen. It is not physically possible for you to sprout a third arm so that reality is never split off.
So, following that logic, we can determine that there is a finite number of realities that can split from one situation. Continuing that logic, if the Multi-World Theory is correct, there are a finite number of alternate realities. While the number of realities would be astronomical, it would still be finite.
So that reality where you're a small, blue alien with antennae is probably not out there.