diff --git a/core/modules/block/custom_block/custom_block.info b/core/modules/block/custom_block/custom_block.info
new file mode 100644
index 0000000..f9e8f05
--- /dev/null
+++ b/core/modules/block/custom_block/custom_block.info
@@ -0,0 +1,6 @@
+name = Custom Block
+description = Allows the ability to create custom blocks through the block interface.
+package = Core
+version = VERSION
+core = 8.x
+dependencies[] = block
diff --git a/core/modules/block/custom_block/custom_block.module b/core/modules/block/custom_block/custom_block.module
new file mode 100644
index 0000000..8db2989
--- /dev/null
+++ b/core/modules/block/custom_block/custom_block.module
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * Implements hook_theme().
+ */
+function custom_block_theme($existing, $type, $theme, $path) {
+  return array(
+    'custom_block_block' => array(
+      'variables' => array('body' => NULL, 'format' => NULL),
+    ),
+  );
+}
+
+/**
+ * Returns HTML for a custom block.
+ *
+ * @ingroup themeable
+ */
+function theme_custom_block_block($variables) {
+  $body = $variables['body'];
+  $format = $variables['format'];
+
+  return check_markup($body, $format);
+}
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlock.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlock.php
new file mode 100644
index 0000000..a69817b
--- /dev/null
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Plugin/block/block/CustomBlock.php
@@ -0,0 +1,104 @@
+<?php
+
+namespace Drupal\custom_block\Plugin\block\block;
+
+use Drupal\block\BlockBase;
+use Drupal\Core\Annotation\Plugin;
+use Drupal\Core\Annotation\Translation;
+
+/**
+ * @Plugin(
+ *  id = "custom_block",
+ *  subject = @Translation("Custom Block"),
+ *  module = "custom_block",
+ *  settings = {
+ *    "status" = TRUE,
+ *    "info" = "",
+ *    "body" = "",
+ *    "format" = "",
+ *  }
+ * )
+ */
+class CustomBlock extends BlockBase {
+
+  /**
+   * Implements BlockInterface::getDefinition().
+   */
+  public function getDefinition() {
+    $definition = parent::getDefinition();
+    $definition['subject'] = $this->configuration['info'];
+    return $definition;
+  }
+
+  /**
+   * Implements BlockInterface::getConfig().
+   */
+  public function getConfig() {
+    $this->configuration = parent::getConfig();
+    $block = db_select('block_custom', 'b')
+    ->fields('b')
+    ->condition('bid', $this->configuration['bid'])
+    ->execute()
+    ->fetchAssoc();
+    $this->configuration['info'] = $block['info'];
+    $this->configuration['body'] = $block['body'];
+    $this->configuration['format'] = $block['format'];
+    return $this->configuration;
+  }
+
+  /**
+   * Implements BlockInterface::configure().
+   */
+  public function configure($form, &$form_state) {
+    $form = parent::configure($form, $form_state);
+    $form['settings']['info'] = array(
+      '#type' => 'textfield',
+      '#title' => t('Block description'),
+      '#required' => TRUE,
+      '#default_value' => $this->configuration['info'],
+      '#description' => t('A brief description of your block. Used on the <a href="@overview">Blocks administration page</a>.', array('@overview' => url('admin/structure/block'))),
+    );
+    $form['settings']['body'] = array(
+      '#type' => 'text_format',
+      '#title' => t('Block body'),
+      '#default_value' => $this->configuration['body'],
+      '#format' => isset($this->configuration['format']) ? $this->configuration['format'] : filter_default_format(),
+      '#description' => t('The content of the block as shown to the user.'),
+      '#rows' => 15,
+      '#required' => TRUE,
+    );
+    $form['settings']['title']['#description'] = t('The title of the block as shown to the user.');
+    return $form;
+  }
+
+  /**
+   * Implements BlockInterface::configureSubmit().
+   */
+  public function configureSubmit($form, &$form_state) {
+    parent::configureSubmit($form, $form_state);
+    $block = array(
+      'info' => $form_state['values']['info'],
+      'body' => $form_state['values']['body']['value'],
+      'format' => $form_state['values']['body']['format'],
+    );
+    if (isset($this->configuration['bid'])) {
+      $block['bid'] = $this->configuration['bid'];
+      drupal_write_record('block_custom', $block, array('bid'));
+    }
+    else {
+      drupal_write_record('block_custom', $block);
+      $this->configuration['bid'] = $block['bid'];
+    }
+  }
+
+  /**
+   * Implements BlockInterface::build();
+   */
+  public function build() {
+    return array(
+      '#theme' => 'custom_block_block',
+      '#body' => $this->configuration['body'],
+      '#format' => $this->configuration['format'],
+    );
+  }
+}