Death of the first born?
Since to have inherited the title of Pharaoh, The Pharaoh must have been a first born son in his family, unless of course he was illegitimate, foreign or transsexual, when god sent that particular plague on Egypt and he did not DIE!
Or else it never happened and was a shit made up Bile-bull fairy story
Also this....
The Buy-bull is full of such logical inconsistencies. But don't bother pointing them out to the acolytes; they won't hear it/see it/accept it/understand it.