"to bewitch us with it"—the verse.

Qatada’s Tafsir: The flood (al-tufan) is the water which God sent upon them until they were standing in it. They called upon Moses, so he invoked his Lord, and He lifted it from them. Then they returned to the worst of what they were doing, so God sent the locusts upon them, which ate most of their crops and fruits. They called upon Moses, so he invoked his Lord, and He lifted it from them. Then they returned to the worst of what they were doing, so God sent the lice—which is the 'dubay' (small locusts)—upon them, and it ate what the locusts had left of their crops and licked them clean. They called upon Moses, so he invoked his Lord, and He lifted it from them. Then they returned to the worst of what they were doing, so God sent the frogs upon them until they filled their beds and their courtyards. They called upon Moses, so he invoked his Lord, and He lifted it from them. Then they returned to the worst of what they were doing, so God sent the blood upon them, and they would not scoop from their water without it being red blood. It was even mentioned to us that Pharaoh gathered two men, one an Israelite and the other a Copt, over a single vessel, and what was in front of the Israelite was water, while what was in front of the Copt was blood. They called upon Moses, so he invoked his Lord, and He lifted it from them.

"Distinct signs": The punishment would come to them, and they would be [subject to it] for eight days and their nights, with one month between every two punishments.