diff --git a/programs/world/src/lib.rs b/programs/world/src/lib.rs
index 5d4ca64..3fbd2bd 100644
--- a/programs/world/src/lib.rs
+++ b/programs/world/src/lib.rs
@@ -36,7 +36,7 @@ pub mod world {
     }
 
     #[allow(unused_variables)]
-    pub fn add_entity(ctx: Context<AddEntity>, extra_seed: Option<String>) -> Result<()> {
+    pub fn add_entity(ctx: Context<AddEntity>, Option<Vec<u8>>) -> Result<()> {
         require!(
             ctx.accounts.world.key() == ctx.accounts.world.pda().0,
             WorldError::WorldAccountMismatch
@@ -132,7 +132,7 @@ pub struct InitializeNewWorld<'info> {
 }
 
 #[derive(Accounts)]
-#[instruction(extra_seed: Option<String>)]
+#[instruction(extra_seed: Option<Vec<u8>>)]
 pub struct AddEntity<'info> {
     #[account(mut)]
     pub payer: Signer<'info>,
@@ -142,7 +142,7 @@ pub struct AddEntity<'info> {
         None => world.entities.to_be_bytes()
     },
     match extra_seed {
-        Some(ref seed) => seed.as_bytes(),
+        Some(ref seed) => seed,
         None => &[],
     }], bump)]
     pub entity: Account<'info, Entity>,