Snap


 * "I'm a survivor."

"Who wants to murder trillions."

"With all six Stones, I could simply snap my fingers. They would all cease to exist. I call that mercy."
 * ―Thanos and Doctor Strange

The Snap was the massive fallout across all civilizations and species in the universe, which wiped out fifty percent of all life in random succession after the Infinity Gauntlet was activated. The mass genocide was initiated by Thanos at the end of the Battle of Wakanda, marking the end of his campaign to retrieve all six Infinity Stones.

Plot
In his quest to obtain the Infinity Stones, Thanos invaded Nidavellir and forced the Dwarves to create the Infinity Gauntlet, a golden glove capable of harnessing the power of the Infinity Stones. Thanos later massacred every single one of them, save for Eitri. After Thanos invaded Xandar, destroyed the Nova Corps, and stole the Power Stone from the Orb, he slaughtered half of the Xandarians as part of his desire to balance the universe.

After having retrieved the Power Stone, Thanos and the Black Order intercepted the Statesman, which was carrying the Asgardian survivors of the cataclysm, Ragnarök. While the Black Order slaughtered half of the ship's population, Thanos personally confronted and defeated Thor, the new king of the Asgardians with Asgard having been destroyed. After easily defeating Hulk in single combat, he murdered Heimdall after he used his last breath to send Hulk back to Earth by way of the Bifrost. He then forced Loki to give up the Tesseract by threatening to kill Thor. After Loki gave it to him and then tried to kill him, he murdered Loki as well. Thanos crushed the Tesseract in his hand, revealing the Space Stone as its power source. Having gained the next stone, he destroyed the Statesman with the Power Stone, leaving Thor and the dead Asgardians in space.

On Earth, Hulk, who was saved by Heimdall's Bifrost Bridge, crashed into the New York Sanctum and warned the Masters of the Mystic Arts of Thanos' incoming arrival. Doctor Strange, Wong, Iron Man and Hulk gathered at the Sanctum and discussed the history of the Infinity Stones' history across the Nine Realms. However, Ebony Maw and Cull Obsidian launched an assault in New York City, prompting the four to fight back. During the ensuing battle, however, Doctor Strange was abducted by Ebony Maw, while Wong sent Cull Obsidian through a portal to the Arctic. Iron Man and Spider-Man, who left his school bus to help them, managed to sneak onto the Q-Ship. Eventually, Iron Man and Spider-Man rescued Doctor Strange and created a hole in the ship which sucked Maw into deep space, killing him. The three then decided to confront Thanos on his home planet, Titan. In Edinburgh, Vision and Scarlet Witch were ambushed by Proxima Midnight and Corvus Glaive, who attempted to draw the Mind Stone out of Vision's head. The couple then received combined reinforcements from Captain America, Black Widow and Falcon. Thanos' two children retreated and the five Avengers traveled to the New Avengers Facility to discuss the Mind Stone.

Meanwhile, Thanos personally traveled to Knowhere to obtain the Reality Stone, which was entrusted to the Collector after the conclusion of the Second Dark Elf Conflict. He infiltrated the Collector's museum and located the Reality Stone, which was in the form of the Aether. He then solidified the Aether into the Reality Stone and added it to his Infinity Gauntlet. As Peter Quill, Gamora, Drax the Destroyer, and Mantis arrived on Knowhere to confront Thanos, he conjured a false illusion of him interrogating and torturing the Collector into revealing the location of the Stone, having accurately predicted that the Guardians of the Galaxy would pursue him to Knowhere.

The illusion worked perfectly and Thanos abducted Gamora and forced her to divulge the location of the Soul Stone with the threat of torturing her sister Nebula with the Power and Space Stones. Thanos' threat forced her to reveal the stone's location, which was hidden on Vormir. Thanos and Gamora then traveled to the mysterious planet, where they were greeted by the Red Skull, who became the stone's guardian as a punishment for abusing the Tesseract's power during World War II. After hearing Red Skull's elucidation that he would have to sacrifice someone he loved in order to obtain the Infinity Stone, he tearfully threw Gamora from the cliff and was granted possession the Soul Stone.

On Earth, the Avengers traveled to Wakanda and tasked Shuri with removing Vision's stone so it could be destroyed without killing him. However, Wakanda soon was attacked by the Black Order and Thanos' army of Outriders, who demanded the Mind Stone. Led into battle by Captain America, Bucky Barnes, Black Panther, the Dora Milaje, Jabari Tribe, Border Tribe, and the Wakandan Royal Guard fought back. Thor arrived on Wakanda with his newly forged weapon Stormbreaker, along with Rocket Raccoon and Groot. The Outriders and the remaining members of the Black Order were eventually defeated and killed. Meanwhile, on Titan, Thanos was confronted by the combined efforts of Doctor Strange, Iron Man, Spider-Man, Star-Lord, Drax the Destroyer, Mantis, and Nebula. Although the seven managed to briefly overwhelm Thanos, he used the power of the four stones to gain the upper hand. A beaten Doctor Strange then relinquished the Time Stone to Thanos so that he wouldn't kill Stark. Having obtained the fifth stone, Thanos used the Space stone to teleport himself to Wakanda.

In the forests of Wakanda, Thanos appeared and used the stones to subdue the Avengers before making his way to Scarlet Witch, who was using her powers to destroy the Mind Stone in Vision's forehead. Although she managed to destroy the last stone and Vision with it, Thanos used the Time Stone to reverse Wanda's destruction, restoring Vision to life and repairing the Mind Stone. After extracting the stone and killing Vision, Thanos completed the Infinity Gauntlet with all six stones and prepared to use it but was caught aback when Thor brutally attacked him with Stormbreaker, momentarily disarming the Mad Titan.

As Thor confronted and reminded Thanos that he made a promise to kill him for his actions during the Attack on the Statesman, including his murders of Heimdall, Loki, and half of the Asgardians, Thanos simply taunted him that Thor should have aimed for his head to ensure his swift death. Recovering from his injury, Thanos, much to Thor's horror, snapped his fingers to activate the Infinity Gauntlet and passed out.

He awakened in the Soulworld where he approached a younger Gamora, who asked him if he completed his mission, to which he solemnly replied yes. Gamora asked what it cost him, to which he replied "everything". Thanos then returned to his consciousness and, his plan complete, used the Space Stone to escape Wakanda travel to the Garden.