Cuicas are friction drums. The drum head has a stick fixed in the middle protruding into the drum. This stick is rubbed with a damp cloth to produce the distinctive sound of a cuica.
Cuicas have their roots in Africa but are now best known for adding colorful background to samba other Brazilian styles of music. A cuica produces a sound similar to what I imagine would happen if you repeatedly squeezed a monkey.
Some love it, some hate it. Guaranteed you won't forget it when you hear it.