The downside is the enchantment has to survive until your upkeep and it only triggers if one opponent has three or more creatures
Blasphemous Act can cheaply reset the board if things get out of control, and the Primsari deck rounds itself out with cheap but notable cards such as Brainstorm , Faithless Looting and Resculpt so it has something to do in the early game
Fear of Imposters The counterspell-creature is another classic sub-genre which has been getting fresh attention over the past few years
Heroic Intervention If you're looking for a green way to keep your board safe, Heroic Intervention is the go-to
Sometimes it impacts opponent delirium, and you even get some incidental lifegain which is never bad
If a replacement effect prevents a card from going to the graveyard (Rest in Peace, for example), then these creatures never go to the graveyard