Normal or no ?

So my almost-ten-month-old little guy has recently started doing this funny thing where he’ll like, clench his fists down at his sides and like, tense up/stiffen/strain his upper body, and sometimes he will get slightly red in the face, almost as though he’s really angry or something, but I noticed him doing that once or twice for no real reason as well.

It’s actually kind of funny and cute, but also lowkey worrisome, sound like a normal baby thing or something else?