I personally run Spawnsire of UlamogSpawnsire of Ulamog in my Kruphix, God of HorizonsKruphix, God of Horizons deck, but only because I've run it by my group and they've all agreed that it's hilarious to dump a bunch of random Eldrazi onto the battlefield
Mana Drain is exceptionally strong, and most other Magic counterspells cost far more and do far less
There are not that many creatures that are sufficiently cheap that you can afford to play them in a similar capacity to something like a Preordain
The intended target of an attack is also important for judging its power
Tapped dual lands are commonly played in Pauper, so this isn't much of a downside
While it lends itself best to a mono-green strategy due to only allowing extra basic Forest plays, it would be a welcome addition to Enchantress decks due to the second ability sacrificing for two green mana