Regenerate

Regenerate is a former evergreen keyword action until it was removed from evergreen status after Oath of the Gatewatch.

Regeneration is a replacement effect which means: "The next time this permanent would be destroyed this turn, it isn't. Instead tap it, remove all damage from it, and remove it from combat."

History
Regenerate appears mostly on black cards or green cards, though it appeared on white cards early in Magic 's history and again in Planar Chaos. The primary color of regenerate was green, secondary was black, and tertiary was white.

Regeneration was designed by Richard Garfield for Alpha. Regeneration has historically been a confusing effect. Originally, regeneration was an ability that only could be activated in the damage prevention step, which was a step right after damage was dealt, to save a creature that would otherwise go to the graveyard. It could not be activated nor triggered any other time. In the Sixth Edition rules changes, the damage prevention step became obsolete, and damage was no longer "assigned" before being dealt - it was simply dealt. Damage prevention, regeneration, and other spells and abilities that generated replacement effects were now played just like other instants. As such, regeneration had drifted in flavor; instead of regenerating when a creature was about to die, you set a regenerative shield that would save the creature if it would die that turn.

As Aaron Forsythe stated, "The word 'regenerate' has been tossed onto cards for years as if it was one of the most simple concepts in the game, along the lines of 'attack' and 'graveyard.' The truth is that the mechanic is so complicated and wonky that we would never greenlight it today, but it has been grandfathered into the fabric of the game, and it does fill a nice niche."

Starting with Kaladesh, regeneration was finally retired. Instead, the phrase “gain indestructible until end of turn” came into being for new but similar cards. This also means that cards will no longer be made which include the phrase "can't be regenerated".

Rulings

 * An effect which says something "can't be regenerated" means that the Regenerate replacement effect won't be applied to that creature even if one is active. If something "can't be regenerated", you can still cast spells and activate abilities that produce a Regenerate effect, but they just won't do anything useful.

Enchantments that grant just regeneration
Target creature Aura (enchanted creature)
 * Broken Fall
 * Fanatical Devotion
 * Horror of Horrors
 * Molting Skin
 * Blessing of Leeches
 * Fortitude
 * Jolrael's Favor
 * Regeneration
 * Soul Channeling</c>
 * Strands of Undeath</c>
 * Trollhide</c>