My son threw precisely ONE tantrum.
I picked him up bodily and put him in the shower stall, and turned on the cold water.
That made him sputter to a stop and ask my why I did that....
I asked him... "is that what you expected me to do?
"no," he replied.
"well, " I explained, "I promise you that when you act like that you can NEVER know what to expect."
All children are manipulation machines, trying to figure out strategies that will get them their way.
The ONLY power any parent has is that, for the first 10 years or so, we get to CHOOSE which of their strategies we will allow to be effective.
Parents who allow a tantrum to be effective are simply not good parents.