diff --git a/src/fot/decoder.rs b/src/fot/decoder.rs
index 7800edf..b4ebac2 100644
--- a/src/fot/decoder.rs
+++ b/src/fot/decoder.rs
@@ -10,7 +10,7 @@ pub trait Decoder: Sized {
 
 pub trait DecoderOpt<Opt>: Sized {
     fn decode(raw: &Raw, offset: usize, size: usize, opt: Opt) -> Result<Self>;
-    fn encode(&self) -> Result<Raw>;
+    fn encode(&self, opt: Opt) -> Result<Raw>;
     fn get_enc_size(&self) -> usize;
 }
 
diff --git a/src/fot/entity.rs b/src/fot/entity.rs
index 3c0562f..3f007b5 100644
--- a/src/fot/entity.rs
+++ b/src/fot/entity.rs
@@ -1,13 +1,12 @@
 use super::decoder::DecoderOpt;
 use super::entitylist::{EntityEncoding, EntityList};
 use super::esh::ESH;
-use super::fstring::FString;
 use super::raw::Raw;
 use super::stream::{ReadStream, WriteStream};
-use super::tag::Tag;
-use anyhow::anyhow;
 use anyhow::Result;
 
+const NO_FLAGS: u32 = 0;
+
 pub struct Entity {
     pub flags: u32,
     pub type_idx: usize,
@@ -15,18 +14,45 @@ pub struct Entity {
     enc_size: usize,
 }
 
-impl DecoderOpt<&EntityList> for Entity {
-    fn decode(raw: &Raw, offset: usize, _: usize, opt: &EntityList) -> Result<Self> {
+impl DecoderOpt<&mut EntityList> for Entity {
+    fn decode(raw: &Raw, offset: usize, _: usize, opt: &mut EntityList) -> Result<Self> {
         let mut rd = ReadStream::new(raw, offset);
-
-        todo!();
+        Ok(match opt.get_entity_encoding() {
+            EntityEncoding::File => {
+                let flags = NO_FLAGS;
+                let type_idx = opt.add_or_get_type(rd.read(0)?);
+                let esh: ESH = rd.read(0)?;
+                let enc_size = rd.offset() - offset;
+                Entity { flags, type_idx, esh, enc_size }
+            },
+            EntityEncoding::World => {
+                let flags = rd.read_u32()?;
+                let type_idx = rd.read_u16()? as usize;
+                let esh: ESH = rd.read(0)?;
+                let enc_size = rd.offset() - offset;
+                Entity { flags, type_idx, esh, enc_size }
+            }
+        })
     }
 
-    fn encode(&self) -> Result<Raw> {
-        todo!();
+    fn encode(&self, opt: &mut EntityList) -> Result<Raw> {
+        let mut wd = WriteStream::new(self.get_enc_size());
+        match opt.get_entity_encoding() {
+            EntityEncoding::File => {
+                wd.write(opt.get_entity_tag())?;
+                wd.write(opt.get_type_name(self.type_idx))?;
+                wd.write(&self.esh)?;
+            },
+            EntityEncoding::World => {
+                wd.write_u32(self.flags)?;
+                wd.write_u16(self.type_idx as u16)?;
+                wd.write(&self.esh)?;
+            }
+        }
+        Ok(wd.into_raw(0, 0))
     }
 
     fn get_enc_size(&self) -> usize {
-        todo!();
+        self.enc_size
     }
 }
diff --git a/src/fot/entitylist.rs b/src/fot/entitylist.rs
index 85bed0a..295e076 100644
--- a/src/fot/entitylist.rs
+++ b/src/fot/entitylist.rs
@@ -16,23 +16,23 @@ pub enum EntityEncoding {
 pub struct EntityList {}
 
 impl EntityList {
-    fn get_entity_encoding(&self) -> EntityEncoding {
+    pub fn get_entity_encoding(&self) -> EntityEncoding {
         todo!();
     }
 
-    fn get_entity_tag(&self) -> &Tag {
+    pub fn get_entity_tag(&self) -> &Tag {
         todo!();
     }
 
-    fn add_new_type(&mut self, name: FString) -> usize {
+    pub fn add_new_type(&mut self, type_name: FString) -> usize {
         todo!();
     }
 
-    fn add_or_get_type(&mut self, name: FString) -> usize {
+    pub fn add_or_get_type(&mut self, type_name: FString) -> usize {
         todo!();
     }
 
-    fn get_type_name(&self, type_idx: usize) -> &FString {
+    pub fn get_type_name(&self, type_idx: usize) -> &FString {
         todo!();
     }
 }