Someone in the casual forum told me that equilibrium cannot bounce the creature that triggers it. I think that they are right, but is this true?
To explain why: Equilibrium triggers when a creature spell is played, not when a creature comes into play. Since it triggers when the creature spell is played, it will resolve before the creature spell resolves and puts the creature into play. So, you cannot return the creature you just played, as it is never in play for Equilibrium to return it.