"ザッツ!超常" is M!LK at their most hyper, a song about having a best friend so good it feels supernatural. The title mixes English and Japanese: ザッツ is "that's", and 超常 (choujou) means "supernatural" or "paranormal". So the hook is basically "That's paranormal!", shouted about something as ordinary as hanging out with your buddy.
The joke the whole song runs on is that nothing special is happening. The narrator says "何にもない日がいいよね" (a day with nothing going on is the best, right?) and wants to "ありふれた景色 集めて帰ろう" (collect ordinary scenery and head home). Two mismatched people, "デコボコ同士" (dekoboko literally means "bumpy and dented", a cute way to say an odd couple), are loud every single day, and somehow that adds up to being "なんだかんだ無敵" (invincible, one way or another).
My favourite bit is the maths. In the first verse they call themselves the 最小公倍数 (lowest common multiple), and in the second they have "ついに見つけた 最大公約数" (finally found the greatest common divisor). It is a nerdy way of saying "we found what we have in common", and it is very funny in a pop song. Watch for "ハマりすぎてんね" too: hamaru is casual slang for being hooked on something, so it means "you're way too into it".
The chorus is pure hype. "あのホシだって掴めちゃう気分" (feels like I could grab that star) and "右肩上がり絶好調バイブス!" (vibes on the rise, in top form!) are a bit much, honestly, but that is the point. 右肩上がり literally means "rising to the right shoulder", the shape of a graph going up. By the end, "奇跡みたいな この日常" (this everyday life that's like a miracle) sums up why a boring day with a friend counts as paranormal.