Swarm of Bats
The Wilds of Rhovanion #41 (x3/x2)

When Revealed: Each player discards each resource from each of his hero's resource pools and raises his threat by 1 for each resource he discarded this way. If no resources were discarded this way, Swarm of Bats gains surge.

Shadow: Attacking enemy gets +1 (+2 instead if the defending character has an attachment).