Revelation 12:3 Then another sign appeared in heaven: an enormous red dragon with seven heads and ten horns and seven crowns on its heads.
Ok neighbor... here it is.... the infamous red dragon with seven heads and ten horns and seven crowns. We don't see those every day!
According to amazingdiscoveries.org, it is satan.
The “great red dragon” is identified in verse 9 as Satan. However, he routinely uses others to persecute, deceive and destroy. Genesis 3:1-13. The “seven heads of ten horns and seven crowns” represents the nations or governments which Satan has used to persecute God’s people. See also Daniel 7:7; Revelation 13:1-5; 17:3. In verse 4 we see an attempt to destroy Jesus at His birth, and can identify Pagan Rome in the person of King Herod as the agency Satan is working through. Matthew 2:13-18. In verse 6 the dragon forces the woman to flee into the wilderness for 1,260 years, the time when Papal Rome is in power persecuting God’s faithful church. Even though he uses others as his agents, the dragon is Satan.
The easy English site agrees. it's satan himself.
The next sign that John saw was a great red dragon. The dragon had 7 heads and 10 horns. Each head had a crown on it. This is a description of the last great world government. It will be a kingdom that unites 10 separate kingdoms (Daniel 7:7-8; Daniel 7:24). At the same time, the dragon means someone in particular. The person who gives power to that kingdom is Satan. So, the great red dragon means Satan.
This is from GodVine. [There are a couple other more in depth commentaries on this site as well.]
And behold a great red dragon - His fiery - red colour denoting his disposition. Having seven heads - Implying vast wisdom. And ten horns - Perhaps on the seventh head; emblems of mighty power and strength, which he still retained. And seven diadems on his heads - Not properly crowns, but costly bindings, such as kings anciently wore; for, though fallen, he was a great potentate still, even the prince of this world.
I went to the google again and found this statement.
Revelation 12:3-17 is a concise history of Satan’s efforts to thwart God’s plan to bring many humans to glory as part of His eternal family. Satan’s actions included convincing a third of the angels to follow him in his attempt to make himself like God, attempting to have Christ killed as a child (Matthew 2:13-18), working to deceive the entire world and persecuting God’s people. Let’s now consider in greater detail Satan’s attempts to derail God’s plan.
I found this picture while searching the commentaries....