John sees a huge beast rising out of the sea and, boy, is this sucker ugly. It has seven heads and ten horns with a crown on each one. It looks kind of like a leopard, but has feet like a bear, and a mouth like a lion. It also loves to say terrible and blasphemous things about God. So, it's all-around awful.
The Dragon gives the Sea Beast its power and, naturally, everyone on Earth is totally amazed by it. They all worship the Sea Beast and the Dragon and don't think there's anyone in the world who can beat them. (Spoiler alert: there is.)
John tells us that the Sea Beast loves to attack Christians and make them into martyrs. Not a good idea, Sea Beast.
He knows that the Sea Beast can be seductive at times (after all, those ten horns do look fetching), but John reminds Christians they'd be better off dead than worshipping the Sea Beast. He means this literally, of course.
This Beast probably symbolizes the Roman Emperors, some of whom liked to persecute Christians, and all of whom promoted Roman religion instead of Christianity (source, p. 1297).
Even More Beastly
Next, another beast comes out of the Earth.
This one has two horns like the Lamb, but sounds an awful lot like the Dragon.
The Earth Beast is kind of like the right-hand creature of the Sea Beast—it makes everyone worship the Sea Beast. This sucker is bad news.
It tries to get you to turn your back on God. Maybe it even wants you to use some of those coins with the emperor's face on him. You know, the ones that say the emperor is actually a god in human form. But don't do it.
John gives us one final bit of info about this Beast—you can find out its true identity by knowing its number—666. Quick, get your Bible decoder ring!
Actually, this Beast probably represents the priests of Roman religion who supported the Emperors and increased the pressure on Christians to take part in the official religion of the Empire (source, p. 1298).