diff --git a/MarathonData.md b/MarathonData.md
index 852aecb..0b04d82 100644
--- a/MarathonData.md
+++ b/MarathonData.md
@@ -391,10 +391,10 @@ main menu, and physics files. Here is a listing of all chunks used within them:
 | `ShPa` | Not analyzed (shapes)                                              |
 | `MMLS` | Not analyzed (MML scripts)                                         |
 | `LUAS` | Not analyzed (Lua scripts)                                         |
-| `FXpx` | Effect definitions                                                 |
+| `FXpx` | Array of Effect Definition                                         |
 | `MNpx` | Monster definitions                                                |
 | `PRpx` | Player definitions                                                 |
-| `PXpx` | Physics definitions                                                |
+| `PXpx` | Array of Physics Definition                                        |
 | `WPpx` | Weapon definitions                                                 |
 | `PICT` | Picture Resource                                                   |
 | `clut` | Unused(?)                                                          |
@@ -976,6 +976,21 @@ Physics Definition is 104 bytes.
 | `PlayerSplash` | `fixed`    | `96`   |
 | `HalfCamSep`   | `fixed`    | `100`  |
 
+### Effect Definition ###
+
+Effect Definition is 14 bytes.
+
+| Name           | Type       | Offset |
+| ----           | ----       | ------ |
+| `Collection`   | `u16`      | `0`    |
+| `Shape`        | `u16`      | `2`    |
+| `Pitch`        | `fixed`    | `4`    |
+| `Flags`        | `u16`      | `8`    |
+| `Delay`        | `u16`      | `10`   |
+| `DelaySound`   | `u16`      | `12`   |
+
+- `Flags` is an Effect Definition Flags bit field.
+
 ## Images ##
 
 ### Picture Resource ###
@@ -1925,4 +1940,14 @@ most sensible for, for instance, lava which can be drained.
 If I could explain to you why there are this many flags, I gladly would, but
 this actually hurts my head.
 
+### Effect Definition Flags ###
+
+| Name              | Bit  |
+| ----              | ---  |
+| `EndOnLoop`       | `0`  |
+| `EndOnXferLoop`   | `1`  |
+| `SoundOnly`       | `2`  |
+| `MakeTwinVisible` | `3`  |
+| `MediaEffect`     | `4`  |
+
 <!-- EOF -->
diff --git a/src/main.rs b/src/main.rs
index ebffeb3..0761722 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -64,6 +64,7 @@ fn dump_chunk(opt: &Options, cid: Ident, cnk: &[u8], eid: u16) -> ResultS<()>
          b"plat" => make_yaml(opt, &rd_array(cnk, map::read_plat)?)?,
          b"term" => make_yaml(opt, &rd_array(cnk, trm::read_term)?)?,
          b"PXpx" => make_yaml(opt, &rd_array(cnk, phy::read_pxpx)?)?,
+         b"FXpx" => make_yaml(opt, &rd_array(cnk, phy::read_fxpx)?)?,
          _ => (),
       }
    }
diff --git a/src/marathon/phy.rs b/src/marathon/phy.rs
index 2d4fd9f..cc23d70 100644
--- a/src/marathon/phy.rs
+++ b/src/marathon/phy.rs
@@ -1,4 +1,5 @@
-use crate::{durandal::{err::*, fixed::*}};
+use crate::{durandal::{bin::*, err::*, fixed::*}};
+use bitflags::bitflags;
 use serde::Serialize;
 
 pub fn read_pxpx(b: &[u8]) -> ResultS<(Physics, usize)>
@@ -39,6 +40,23 @@ pub fn read_pxpx(b: &[u8]) -> ResultS<(Physics, usize)>
                vel_bkw, vel_fwd, vel_prp, vel_rec, vel_trm}, 104))
 }
 
+pub fn read_fxpx(b: &[u8]) -> ResultS<(Effect, usize)>
+{
+   read_data! {
+      14, BE in b =>
+      collection = u16[0];
+      shape      = u16[2];
+      pitch      = Fixed[4];
+      flags      = u16[8];
+      delay      = OptShort[10];
+      delay_snd  = OptShort[12];
+   }
+
+   let flags = ok!(EffectFlags::from_bits(flags), "bad EffectFlags")?;
+
+   Ok((Effect{collection, shape, pitch, flags, delay, delay_snd}, 14))
+}
+
 #[derive(Debug, Serialize)]
 pub struct Physics
 {
@@ -70,4 +88,27 @@ pub struct Physics
    pub vel_trm: Fixed,
 }
 
+#[derive(Debug, Serialize)]
+pub struct Effect
+{
+   pub collection: u16,
+   pub shape:      u16,
+   pub pitch:      Fixed,
+   pub flags:      EffectFlags,
+   pub delay:      OptShort,
+   pub delay_snd:  OptShort,
+}
+
+bitflags! {
+   #[derive(Serialize)]
+   pub struct EffectFlags: u16
+   {
+      const EndOnLoop       = 1;
+      const EndOnXferLoop   = 1 << 1;
+      const SoundOnly       = 1 << 2;
+      const MakeTwinVisible = 1 << 3;
+      const MediaEffect     = 1 << 4;
+   }
+}
+
 // EOF