UO.EnemyID
From OpenEUO
UO.EnemyID
⇒ Returns the ID of a current enemy mobile.
Note: It is only possible to see one enemy at a time using this variable. If you have more than one enemy, the variable will switch ID's randomly. Under current version and earlier (0.9s), if you utilize a pet, UO.EnemyID may actually reflect the pet's ID in lieu of that of an enemy so always double check the returned value.