Rakdos Joins Up + Opalescence + Mercurial Pretender

Rakdos Joins Up

Opalescence

Mercurial Pretender

How it works

1. Cast Mercurial Pretender by paying its mana cost. Choose to have it enter the battlefield as a copy of Rakdos Joins Up.
2. Put Mercurial Pretender into your graveyard due to the legend rule.
3. Mercurial Pretender's first ability and second ability trigger, along with Rakdos Joins Up's second ability.
4. Resolve Mercurial Pretender's second trigger and Rakdos Joins Up's trigger, dealing damage to target opponent.
5. Resolve Mercurial Pretender's first trigger, returning it from your graveyard to the battlefield with two +1/+1 counters on it as a copy of Rakdos Joins Up.
6. Repeat from step 2.

This loop transforms the legendary enchantment Rakdos Joins Up into an explosive engine by leveraging the state-based legend rule to continuously sacrifice copies and trigger their own recursion. When you cast Mercurial Pretender and have it enter as a copy of Rakdos Joins Up, the legend rule immediately puts it into your graveyard—but crucially, its own enters-the-battlefield trigger still goes on the stack to pull itself right back out with extra +1/+1 counters. Meanwhile, Opalescence works behind the scenes to turn these enchantments into creatures, making the loop self-sustaining while the repeated deaths fuel infinite damage targeting your opponent.