A.T. Robertson Commentary Revelation 8:10

"And the third angel sounded, and there fell from heaven a great star, burning as a torch, and it fell upon the third part of the rivers, and upon the fountains of the waters;" — Revelation 8:10 (ASV)

Burning as a torch (καιομενος ως λαμπας). See 4:5; Matthew 2:2, perhaps a meteor, striking at the fresh-water supply (rivers ποταμων, springs πηγας) as in the first Egyptian plague also.