Getting back on topic…
>>48294027IMO, there's two options for what Eternatus should have been:
> Ghost/Dragon It has a skeletal appearance and a debatable undead status > Dark/Dragon: Its very existence and power causes chaos when unleashed.However, I think the totally-not-an-Ultra-Beast had a reason for being Poison-type, an in-universe reason instead of just being a reference to nuclear power. Notice how Pokémon who randomly Dynamax tend to go berserk? Not only do some poisons tend to cause such erratic behavior, but so can performance-enhancing drugs or even drugs in general.
That's right folks: Dynamax and Eternatus's typing are a kid-friendly stand in for performance-enhancing drugs used in sports competitions, and Eternatus is a drug dealer!