Hellephant is the correct spelling. "09:00 Death came to claim me, but it tripped on its robe. Time to run away! Farewell, Hellephant!" --BlueStapler 08:18, 1 October 2012 (BST)
Today's Godville Times (Day 1236 g.e.) used Hellaphant:
Today, my hero fought a Hellaphant. "Aha, Hellaphant! Not even death can save you from me!" I guess there should be two articles; one for Hellephant and one for Hellaphant. --BlueStapler (talk) 19:42, 8 November 2013 (GMT)
I believe that Hellephant was removed from the game, keeping Hellaphant as the only spelling, sometime in 2012-2013. The only forum references to Hellephant after this time are not from the game itself; references to Hellaphant continue much longer.