It can be used to cast powerful restricted spells multiple times, give a second life to a creature which has been killed, and even be used to return lands from the graveyard to help mana fix
A 3/4 with vigilance for 4 that also taps for isnt anything to just forget about
The enchantment theme, Rooms, manifest dread, eerie, the return of delirium, impending, glimmers, survival, overlords, and just the whole way it all interacted with a graveyard theme was a huge success, but it was also a lot
It may have to attack every turn it can, but in exchange you get an indestructible creature and another source of card draw like Squidward's
With the addition of Unholy Heat to Modern, not even Lightning Bolt has been able to fully withstand the power creep of the last few years, and I personally would place it below Unholy Heat in power level when taking into consideration the context of the Modern metagame