FTM -need advice

Bri

My son is 1 year old and every once in awhile he’ll be dead asleep and start screaming! Screaming crying and his entire body is stiff, his eyes are closed and he’s still asleep. I have to literally shake him to wake him up, that is the only way to calm him down. Every time it happens I get terrified that something’s wrong

My question is: has anyone experienced this with their LO? Is this “normal” behavior?