Classic NES Series: Castlevania Hints for Gameboy Advance
Medusa Heads are hard to kill, for they move up and down, and since they come at you infinitely, you can't just wait until they are gone. The best way to avoid them is to time it so that you can jump over them, since they usually go through the floor. Or, you can walk under them. If you cannot time it right, walk forward, then back until you are in a good position to get by them.