Golgari Self-Mill Battle for Baldurs Gate signpost Kagha, Shadow Archdruid returns to once again helm the Golgari self-mill archetype
(Whenever you cast a noncreature spell, the token gets +1/+1 until end of turn.) Equip Flurry Whenever you cast your second spell each turn, create a 1/1 white Monk creature token with prowess
I believe this came about because they wanted a mischievous creature on the back that punished the opponent for not having enough cards in their hand, and flavor-wise, that felt a lot like a faerie (it was an imp when it was on Equilor)
They were officially made a creature type with the release of the Ixalan set, and a few older creatures, such as Regal Behemoth, were errata'd to become dinosaurs with this release
Once there, its solely a creature card and doesnt count as a castable spell
The best uses are pumping Phyrexian Germ tokens on living weapon equipment like Batterskull, or looping a creature by feeding it to Mortarpod or Mask of Immolation