What is the drop rate for Medusa in Terraria?

Hello there, I'm curious about something related to the game Terraria. Could you please explain to me what the drop rate for Medusa is? I've been trying to get my hands on one of these items but it seems like it's quite rare. Is there a specific way to increase my chances of getting it? Or is it just a matter of luck and persistence? I'd appreciate any insight you can provide. Thank you in advance!