I don't think I ever named Griever anything all that interesting.

But I used to have a lot of fun with Shiva, because in the Fire Cavern, after you summon Shiva on Ifrit, He exclaims "They have [Shiva]!"

And sometimes at the end as he dies he says "I've underestimated the power of [Shiva]."

So if you call Shiva something like my ass, well...