Homura, Human Ascendant triggers creature ETBs upon returning from graveyard to battlefield (i.e. flipping)

[Zzooouhh]

Self explanatory. Sacrifice Homura to something like Goblin Bombardment and let him hit the GY. Upon returning (he should already return flipped and not trigger creature ETBs), he'll still trigger effects such as Purphoros. The way it appears to work in Xmage is that he returns unflipped and only then flips to his enchantment side.