This is the 11878th most frequent Spanish word.
hormiguero
An "anthill" or "ant nest."
Here, 'hormiguero' refers to an actual anthill, the physical structure that ants create and inhabit.
El hormiguero estaba lleno de actividad debido a la llegada del verano.
The anthill was full of activity due to the arrival of summer.
In this usage, 'hormiguero' is employed metaphorically to describe a crowded place bustling with activity.
La plaza era un hormiguero de gente disfrutando del festival.
The square was a hive of people enjoying the festival.
In this case, 'hormiguero' is used colloquially to refer to the sensation of pins and needles or tingling usually caused by restricted blood flow.