If you have a pet named or of type Shivarra out and the unit saved as your focus target exists then:
Cast Mesmerize on the unit saved as your focus target
Else, if you have a pet named or of type Observer out and the unit saved as your focus target exists then:
Cast Optical Blast on the unit saved as your focus target
Else, if you have a pet named or of type Voidlord out and the unit saved as your focus target exists then:
Cast Disarm on the unit saved as your focus target
Else, if you have a pet named or of type Fel Imp out and the currently targeted unit is a friend then:
Cast Sear Magic on the currently targeted unit
Otherwise:
Cast nothing on the currently targeted unit