Afflict 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
At the beginning of your postcombat main phase, addto your mana pool for each 1 life your opponents have lost this turn.
7/14/2017 Damage dealt to a player causes that player to lose that much life.
7/14/2017 Because it triggers at the beginning of a phase, Neheb’s last ability isn’t a mana ability. It uses the stack and can be countered by effects that interact with triggered abilities, such as that of Nimble Obstructionist.
7/14/2017 You get a postcombat main phase even if no creatures attacked during a turn. Neheb’s last ability will trigger.
7/14/2017 If an opponent loses life but Neheb leaves the battlefield before your postcombat main phase begins, its last ability doesn’t trigger.
7/14/2017 Neheb’s ability checks only how much life opponents lost during the turn, not by how much their life total decreased compared to the start of the turn. For example, if an opponent lost 2 life and then gained 8 life before your postcombat main phase, you’ll add to your mana pool.
7/14/2017 If an opponent loses life and subsequently loses the game before your postcombat main phase, Neheb’s last ability counts that loss of life.
7/14/2017 If you somehow have more than two main phases in a turn, each main phase after your first one is a postcombat main phase, and Neheb’s last ability triggers at the beginning of each of them.
7/14/2017 If multiple creatures block a creature with afflict, afflict triggers only once.
7/14/2017 Afflict causes the defending player to lose life; it’s not damage or combat damage.
7/14/2017 If a creature is attacking a planeswalker, that planeswalker’s controller is the defending player.
7/14/2017 Afflict resolves before combat damage is dealt. If this loss of life brings a player to 0 life or less, that player loses the game immediately. A blocking creature with lifelink won’t deal combat damage in time to save that player.