They're_Clips_Not_Mags
The meme comes from a point in moistcr1tikal's response to Sneako's "unhinged tantrum and meltdown", where the latter pulls out a gun. He can be seen pointing it, and dancing with it and saying "Look at my clips!", in reference to the filled magazine cartridges he then displays.

Moistcr1tikal, seemingly even more exasperated, prepares a "gun anatomy lesson" for the "absolute buffoon". He proceeds to declare the difference between clips and mags, by first pulling out a handgun, then showing an AR with a scope and light attached to it.

The scene quickly went viral, with many fellow content creators expressing their laughter, shock, or interest at moistcr1tikal's power move.
sneako vs moistcr1tikal (meme)