Criptonita is the Spanish word for "Kryptonite," the famous fictional substance that is Superman's only weakness. It's a perfect example of a modern, pop-culture word being used metaphorically in a song.
In the lyrics, the singer calls a person his criptonita to express that they are his one great vulnerability. Despite his tough exterior, this person is the only one with the power to hurt him, making it a powerful and memorable metaphor for a love that makes you weak.
In "CRIPTONITA", Mexican artist Tito Double P sings about that one specific person who completely breaks down your defenses. He calls his ex "mi criptonita" [my kryptonite], a nod to Superman's only real weakness. Even though the relationship did not even last three months ("Ni los tres meses" [Not even three months]) and ended in betrayal ("Otra traición, ya ni me beses" [Another betrayal, don't even kiss me anymore]), he admits she still makes him tremble whenever he thinks about her.
Instead of dealing with the heartbreak quietly, he turns directly to late-night chaos. He spends the night "vaciando unos botes y viendo a la luna" [emptying cans (of beer) and looking at the moon], trying to embrace the madness ("en la puta loquera me quiero quedar" [in the fucking craze I want to stay]). He even brings out party remedies: "Pa' mí un gallón, pa' ellas tequila" [For me a big joint, for them tequila] where "gallón" is Mexican street slang for a large marijuana joint. It is a blunt look at dealing with a toxic spark by turning up the music, grabbing drinks, and leaning into bad habits.