What it does
"Rapid Regeneration" isn't an official Magic keyword, so there's no rules text behind it—you won't find it in the comprehensive rules or on any printed card. It's likely confused with Regeneration, the long-standing mechanic that creates a "shield." When a creature with a regeneration shield would be destroyed (by lethal damage or a "destroy" effect), instead the shield is used: the creature is tapped, removed from combat, and all damage is healed.
The big misunderstanding is what regeneration doesn't stop. It only replaces destruction—it won't save a creature from being exiled, sacrificed, bounced, or reduced to 0 toughness via -X/-X effects. Many removal spells in modern Commander dodge it entirely by using "exile" instead of "destroy."
In Commander, regeneration is a defensive tool against board wipes like Wrath of God, but useless against Damnation-style sacrifice or exile-based sweepers. Always set up the shield before damage or destruction occurs.
