He killed every firstborn child in Egypt.
The LORD smote all the firstborn in the land of Egypt, from the firstborn of Pharaoh that sat on his throne unto the firstborn of the captive that was in the dungeon.... And there was a great cry in Egypt; for there was not a house where there was not one dead. Exodus 12:29-30
He sent fiery serpents to bite and kill people.
And the LORD sent fiery serpents among the people, and they bit the people; and much people of Israel died. Numbers 21:6
He commanded the Israelites to commit genocide.
Thus saith the LORD of hosts ... Now go and smite Amalek, and utterly destroy all that they have, and spare them not; but slay both man and woman, infant and suckling, ox and sheep, camel and ass. 1 Samuel 15:2-3
He forced women to eat their children, and killed prophets, priests, old young and old people, and virgins without pity.
Behold, O LORD, and consider to whom thou hast done this. Shall the women eat their fruit, and children of a span long? shall the priest and the prophet be slain in the sanctuary of the Lord? The young and the old lie on the ground in the streets: my virgins and my young men are fallen by the sword; thou hast slain them in the day of thine anger; thou hast killed, and not pitied. Lamentations 2:20-21
If you don't obey all of his commandments, he will give you horrible diseases and feed your children to your enemies.
I also will do this unto you; I will even appoint over you terror, consumption, and the burning ague, that shall consume the eyes, and cause sorrow of heart: and ye shall sow your seed in vain, for your enemies shall eat it. Leviticus 26:16
And force you to eat your own children.
And thou shalt eat the fruit of thine own body, the flesh of thy sons and of thy daughters. Deuteronomy 28:53
He will force those who oppress you to eat their own flesh and get drunk on their own blood.
And I will feed them that oppress thee with their own flesh; and they shall be drunken with their own blood, as with sweet wine. Isaiah 49:26
He will deal with you in his fury and show no pity. And if you cry to him, he'll ignore you.
Therefore will I also deal in fury: mine eye shall not spare, neither will I have pity: and though they cry in mine ears with a loud voice, yet will I not hear them. Ezekiel 8:18
He will discover your skirts on you face (whatever that means) and show everyone your nakedness. Then he'll cast abominable filth upon you and make you vile.
Behold, I am against thee, saith the LORD of hosts; and I will discover thy skirts upon thy face, and I will shew the nations thy nakedness, and the kingdoms thy shame. And I will cast abominable filth upon thee, and make thee vile. Nahum 3:5-6
And he'll corrupt your seed (cause birth defects?) and spread dung on your faces.
Behold, I will corrupt your seed, and spread dung upon your faces. Malachi 2:3