This is an example of a module being displayed inside the menu dropdowns. This feature can display any module or module position, allowing for multiple modules in the same dropdown.
Mambots have been renamed as Plugins.
Mambots were introduced in Mambo and offered possibilities to add plug-in logic to your site mainly for the purpose of manipulating content. In Joomla! 1.5, Plugins will now have much broader capabilities than Mambots. Plugins are able to extend functionality at the framework layer as well.