Locusts

Allah (swt) sent another sign upon them. After al-ṭūfān: al-jarād. Allah (swt) sent locusts upon them — grasshoppers, locusts. Allah sent clouds of locusts upon them that would block out the sun. And these clouds would march over their fields and eat anything they found in front of them. They would eat all of the plants and the trees in the fields and leave them dead, and then they would march on the houses and eat the wood. Miracles from Allah: destruction that went over Egypt, clouds of locusts marching over the land of Egypt, destroying everything.

They went to Mūsā begging: O Mūsā, ask Allah to release us from this punishment; we are going to believe, and send Banū Isrāʾīl with you. So Allah (swt) released that punishment from them — fa-idhā hum yankuthūn — and they broke their promise again. Look at what Allah (swt) says they said:

Whatever ayah you may bring us, to work therewith your sorcery on us, we shall never believe in you. Wa in yaraw kulla āyatin lā yuʾminū bihā — Allah says about these people: even if they see every sign, they will not believe.