Moses didn't send the plagues. God did. But I believe that the death of the first born would be the worst.
The ten things that God did during the time of Moses were called Plagues.
In Ancient Egypt
Medians
Moses was a poor speaker whom God chose to lead the Israelites out of Egypt. God sent plagues on Egypt through Moses to convince Pharaoh to release the Israelites. Through God's guidance, Moses led the Israelites to freedom from slavery in Egypt.
There were a total of 10 plaques in Egypt , sent by God.
They wanted to find the Promise Land where its green and plenty of water is for all
The people clearly saw the ten plagues ,and the sound of God. So they new Moses was not just a ordinary man he was a person called by god to set them fre of slavery.
Moses told Pharaoh to let the people go free ten times.
Hodges. Connie has written: 'Moses and the 10 Plagues'
moses
God sent the plagues; Moses merely announced them. According to Jewish tradition, the ten plagues were over the span of one year (Mishna, Eiruvin ch.2), ending in the month of Nisan ( ~April), 1312 BCE.