Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
: Regenerate Undercity Troll. (The next time this creature would be destroyed this turn, it isn't. Instead tap it, remove all damage from it, and remove it from combat.)
6/22/2015 Renown won’t trigger when a creature deals combat damage to a planeswalker or another creature. It also won’t trigger when a creature deals noncombat damage to a player.
6/22/2015 If a creature with renown deals combat damage to its controller because that damage was redirected, renown will trigger.
6/22/2015 If a renown ability triggers, but the creature leaves the battlefield before that ability resolves, the creature doesn’t become renowned. Any ability that triggers “whenever a creature becomes renowned” won’t trigger.