Mammoth

A prehistoric version (dinosaur) of a Whale.

Whale:

"A person who spend incredible amount of money in gacha type games which makes him/her ultra powerful and godlike. Commonly used in many reddit mobile game /r."
But a prehistoric

Dinosaur:
"An old person living in a new world."

David Rockefeller is possibly the flushest mammoth.

Flush:
Someone who has loadsa money.