Favorite Monster (Aberration)
Aboleth. Too often, aberrations are built around awesomely bugfuck mechanical features that make them amazingly fun to run (though arguably less fun to fight) in combat. However, those mechanics usually don’t lend a lot to an aberration’s presence outside of combat, or provide a lot of inspiration for ongoing campaign story. Aboleths, when they’re done right, are a big exception to that rule.
For whatever it’s worth, D&D 5e does the aboleth absolutely right.