It is rare you are so flush with suitable discard outlets that you are passing this up
It is a very odd mana rock, because you are spending mana to get 1 less than you spent, but I think the threat here is that it then also becomes an 8/8 that makes opponents start sacrificing permanents, which seems pretty strong, especially since it is safe from creature-based removal until you turn it on
Both of these have been reprinted a few times in sets and plenty of times in other products, as they are simple, but very playable
Indomitable Ancients, in particular, is a monster in a Doran deck, becoming a 10/10 with Vigilance
The first time you cast it, you essentially get to look at four cards and choose two of them for four mana
Your creatures can also double block which Flumph will love a lot, and again works nicely with a big butt