They're not the only ones whose pants are getting tighter…

The thing that makes my pants get constantly tighter at those pictures is the fact that it accurately depicts a rather "common" psychic power (it's already quite advanced, common in the sense "most games with psychics/psions have a version of that"). In D&D, it's known as Fission – You generate a slightly weaker (Your level minus one) double of yourself.

(If you want extra fluff, if the double dies, IIRC you lose a level. If the original dies, the double becomes the original, and you lose an extra level in addition to the "lost" level for allowing your stronger self to eat ass)

So my headcanon is that Sabrina does know Fission and had already shown it in Anime (Kid Sabrina), and her fission self is always one generation behind.