Based on the search results, it seems that the chances of a sea beast spawning depend on certain events or actions. In the game Blox Fruits, sea beasts are sea-related mini-bosses that can be spawned through certain Sea Events, the Summon Sea Beast item, Raids, while fighting the Tide Keeper, and other methods. The odds of two sea beasts spawning at once in the game are considered lucky. However, it is unclear what the exact chances of a sea beast spawning are, as it may vary depending on the specific circumstances in the game. Some players have reported difficulty in finding sea beasts to hunt, while others have found ways to farm them quickly and easily. It is important to note that hacking or cheating to spawn sea beasts is not a legitimate or fair way to play the game.