In their study of the cosmic All, the Arisians realize that the DCU (let's go pre-COIE) is a threat to the rest of the universes. They have defeated Eddore and decide to hang around to take out Oa, as the center of power in the DCU (ignoring the supernatural).

Thus, using the Eddorian dimension slipping techniques (Eddore came from another dimension), they assembly the successful fleets of the Galactic Patrol (millions of battleships), set up a full set of superweapons (sun beams, nega sphere planets, free planets and strange matter planets from other dimensions), engage the full telepathic attack led by the Arisians, the Children of the Lens and the assembled body of Lensmen. FYI, the Arisians are definitionally immune from any physical attack.

They intend to port into Oa's system and start with a sunbeam and then a wave of the various planet projectiles. Then the fleets. At the same time as the superweapons attack, the telepathic attack is launched.

It turns out on Oa, that the full PC GLC is there with 3600 Lanterns and 36 Guardians. They pick up the pending dimensional shift about 15 minutes and go on guard but without knowledge of what is coming. Then the portals open.

What happens? What is the most dangerous attack for the GLC and Guardians to counter?