Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.) If the target creature is an illegal target as Persistent Constrictor's first ability tries to resolve, it won't resolve and none of its effects will happen
Definitely a more complex mechanic, forcing you to take things off the board and bring them back to bolster up your defences
When I did my review of Gatecrashs flavor, I noted the modern (post-1850 in the Common Era) origins of several terms used in card names, among them Five-Alarm Fire, Gridlock, and Smog Elemental
6 Anim Pakal, Thousandth Moon Artifact Synergy And Free Creatures The two parts of Anim Pakal, Thousandth Moon decks are using various buff spells popular in white to make it bigger so that it can create more Gnomes when it hits, while using artifact synergies to buff them all