I needed one for my next game, and couldn't find one on the interwebz. so I made my own.
Astral Dreadnought
Gargantuan fiend, chaotic neutral
AC 20 (natural armor)
Hit Points 20d20+200 (410)
Speed Fly 180 ft.
Str 30 (+10), Dex 7 (-2), Con 30 (+10)
Int 5 (-3), Wis 14 (+2), Cha 18 (+4)...