#flashyflash

Blast explains how the cube operates According to Blast, the cubes act as a transmitter that distort space and allow for communication with God. Anyone who comes in contact with a cube is able to hear the voice of God in their head.

One of the cubes was first seen 18 years ago during a flashback of Tatsumaki when she was saved by Blast from a hybrid monster.Another cube was also found by Saitama, Manako, and Flashy Flash in the rubble of the Monster Association Headquarters.God's voice begins to speak in their heads, saying that if they touch the cube and make a wish, the being will either grant them power, or they will "be confiscated." Immediately afterward, Blast appears and is relieved to find that the group did not accept God's words. He takes the cube, transferring it through a portal to an unknown location.Blast stated that there are multiple cubes scattered around the world, and that he has been collecting them as a hobby.

The cubes appear to be extremely heavy, as one was able to get Flashy Flash's arm stuck, and sunk into solid rock after being dropped by Saitama.Additionally, Manako was unable to lift it back up.

God can grant powers to individuals should they place their hands on one of these mysterious cubes and then state their wishes. However, if they are not worthy to be bestowed upon, they will be "collected."

Various Heroes. 

I found a great meme on the r/OnePunchMan subreddit