Sunstreak Phoenix can alter the day/night cycle and return from the graveyard to the battlefield as days and nights change
Its Bloodthirst ability lets it come in with +1/+1 counters based on damage dealt to your opponents, and its Enrage effect lets it deal damage to an opponent, each time it takes a hit, unless they sacrifice a (non-token) creature
The first is a Bear with first strike and if a foe has more lands you can ramp a Plains to the battlefield and it can get any Plains, so I added a few dual lands
When combined with other effects that prevent their removal, cards like these can become "Hard Lock Pieces" that deterministically prevent your opponent from playing Magic
In particular, one of threshold's problems is that threshold abilities can be turned on and off in the middle of combat, or while on the stack
And while it's obviously a decent plan to put this in a landfall deck that can make better use of the lands it fetches up, there's no sign on EDHREC that it's seeing any play with the Edge of Eternities Landfall commanders