Forced: After the "when revealed" effect of a treachery card is canceled, raise each player's threat by 2.
Shadow: Attacking enemy gets +1 
. If this attack destroys a character, the defending player raises his threat by 2.
Forced: When Ancient Causeway is explored, raise each player's threat by 2.
...on either side of it there were lines of large boulders and hewn stones that screened the travellers almost like a hedge. –The Fellowship of the Ring
When Revealed: Raise each player's threat by the of the active location.
Shadow: Defending player either raise his threat 3, or this attack is considered undefended.
Your enemies lurk somewhere in the decrepit ruins around you: a constant threat until you search them out...
Forced: At the end of the refresh phase, raise each player's threat by 2.
Response: After Search the Ruins is defeated, reduce each player's threat by 3.