It had happened. With a snap of his fingers, the mad titan Thanos had wiped half the life from his home universe. Emptiness plagues New York, with the famous landmarks such as the Avengers tower and the Sanctum Sanctorum being left without anyone inside. And it's at this point that the walls of the multiverse become perilously thin, causing visitors from outsider universes to begin... appearing. There's no blue beam shooting into a portal in the sky, no sudden announcements. It just... happens. First they weren't there, and now the outsiders are unquestionably present within this world. They manifest all over, with no rhyme or reason in where it is they appear. Some are on their feet, some fall from the sky, and some others are brought here while they were in the middle of some other kind of activity in their own reality. They may appear in isolated areas on their own, or right in the middle of a populated zone.
To onlookers, it would appear as though the strange, intimidating, alien beings had appeared out of thin air, with a kind of distortion about them- the same kind you'd see above the road when it's hot out. The distortion would fade out rather quickly, leaving both observers and those who had appeared in equal states of confusion.
One of the foreign beings appears in the middle of a street, more emptied that it should be in a modern day metropolis. The newcome is foreign in appearance, with regal features offset by bright red eyes with serpentine, slitted pupils. His body is covered by a set of ostentatious golden plate armor, matching the color of his blonde, swept-back hair. The King of Heroes, Gilgamesh, appears with a look indicating some amount of shock and surprise on his face. He whirls about, armor and jewelry jangling with the motion, fixing his gaze upon innocent passers-by, who simply duck their heads and continue moving, albeit at a faster pace. They retain bad memories from the last time strange-looking visitors appeared from nowhere.
After a moment of adjustment, particles of dust scatter around his feet as the golden king levitates off the ground, ascending upward. When he clears the rooftops of the buildings around him, a shimmering golden portal forms behind him. A brilliant golden craft emerges from it, like a throne set atop a futuristic airplane. Gilgamesh settles into the seat as his heavenly vessel, his Vimana, cruises slowly through the sky as a blatantly out-of-place sight in an otherwise mundane setting.