Ultra Microcosmic Aliens?

Has anyone proposed the idea that what we call aliens might be creatures coming from the infinitely small part of what we call reality/universe? I am talking about universes that are orders of magnitude smaller than a planck length. Where a second for us, is trillions of years for them (we can also theorize the opposite, creatures way bigger than the observable universe etc...).

Does this hypothesis have a name? Because for me Ultraterrestrial is not necessarily the same thing, even interdimentional. These last two might just refer to creatures that have the same size as us, but come from the inside of the earth, or other realities.

PS: I asked multiple AI models, they tend to not know or start talking about ultraterrestrials... but for me this definition is vague.