"'Oumuamua is in a different category of object. It's much harder to find, but there are a lot more of them."

1st known interstellar visitor 'Oumuamua is an 'exo-Pluto' — a completely new class of object, scientists say

Source: space
Source Link: https://www.space.com/astronomy/dwarf-planets/1st-known-interstellar-visitor-oumuamua-is-an-exo-pluto-a-completely-new-class-of-object-scientists-say