Immediately crashes WP after activating this plugin

I installed it in my staging site, and it crashes right away.

My instance details:

WordPress vers?o 6.4.2
Tema atual: Dez (vers?o 2.3)
Plugin atual: Markdown Comment (vers?o 1.0)
PHP vers?o 8.1.27

Error details (in pt_BR; sorry about that):

Um erro do tipo E_ERROR foi causado na linha 24 do arquivo /srv/htdocs/wp-content/plugins/markdown-comment/markdown-comment.php. Mensagem de erro: Uncaught Error: Class "Parsedown" not found in /srv/htdocs/wp-content/plugins/markdown-comment/markdown-comment.php:24
Stack trace:
#0 /wordpress/core/6.4.2/wp-includes/class-wp-hook.php(326): markdown_comment_converter('Outro teste.', Object(WP_Comment))
#1 /wordpress/core/6.4.2/wp-includes/plugin.php(205): WP_Hook->apply_filters('Outro teste.', Array)
#2 /wordpress/core/6.4.2/wp-includes/comment-template.php(1082): apply_filters('comment_text', 'Outro teste.', Object(WP_Comment), Array)
#3 /wordpress/core/6.4.2/wp-admin/includes/class-wp-comments-list-table.php(950): comment_text(Object(WP_Comment))
#4 /wordpress/core/6.4.2/wp-admin/includes/class-wp-list-table.php(1794): WP_Comments_List_Table->column_comment(Object(WP_Comment))
#5 /wordpress/core/6.4.2/wp-admin/includes/class-wp-comments-list-table.php(671): WP_List_Table->single_row_columns(Object(WP_Comment))
#6 /wordpress/core/6.4.2/wp-admin/includes/class-wp-list-table.php(1724): WP_Comments_List_Table->single_row(Object(WP_Comment))
#7 /wordpress/core/6.4.2/wp-admin/includes/class-wp-list-table.php(1709): WP_List_Table->display_rows()
#8 /wordpress/core/6.4.2/wp-admin/includes/class-wp-comments-list-table.php(604): WP_List_Table->display_rows_or_placeholder()
#9 /wordpress/core/6.4.2/wp-admin/edit-comments.php(452): WP_Comments_List_Table->display()
#10 {main}
 thrown