diff --git a/src/construct/text.rs b/src/construct/text.rs
index a461d02..af04afe 100644
--- a/src/construct/text.rs
+++ b/src/construct/text.rs
@@ -32,7 +32,7 @@ use crate::subtokenize::Subresult;
 use crate::tokenizer::Tokenizer;
 
 /// Characters that can start something in text.
-const MARKERS: [u8; 16] = [
+const MARKERS: [u8; 17] = [
     b'!',  // `label_start_image`
     b'$',  // `raw_text` (math (text))
     b'&',  // `character_reference`
@@ -49,6 +49,7 @@ const MARKERS: [u8; 16] = [
     b'w',  // `gfm_autolink_literal` (`www.` kind)
     b'{',  // `mdx_expression_text`
     b'~',  // `attention` (gfm strikethrough)
+    b':',  // `task` (custom task)
 ];
 
 /// Start of text.
@@ -163,6 +164,13 @@ pub fn before(tokenizer: &mut Tokenizer) -> State {
             );
             State::Retry(StateName::MdxExpressionTextStart)
         }
+        Some(b':') => {
+            tokenizer.attempt(
+                State::Next(StateName::TextBefore),
+                State::Next(StateName::TextBeforeData),
+            );
+            State::Retry(StateName::TaskStart)
+        }
         _ => State::Retry(StateName::TextBeforeData),
     }
 }