Spider balloons are a phenomenon in which spiders spin out long lines of silk, called ballooning or kiting, to catch the wind and become airborne at the mercy of air currents and electric fields). This behavior is primarily used by spiderlings to disperse, but larger individuals have been observed doing so as well). The silk threads released by the spider cause them to become airborne and move through the air).
However, the term "spider balloons" can also refer to Halloween decorations, such as black spider foil balloons, that are sold on websites like Amazon. These decorations are typically used to add a spooky touch to Halloween parties and events.
There are also tutorials available online that show how to make balloon spiders using balloons and other materials.
