THIS IS THAT THING!!!
As you may or may not know I am an upright bass player, and while I hate people confusing my bass for a cello, I love classical strings making their way into pop culture!
And to clear up any confusion, from biggest to smallest: Upright bass, cello, viola, violin.

An upright bass is played standing or sitting on a stool (like a bar stool type thing), a cello is played sitting in a normal chair, and violins and violas are played on the neck and arm.
ANYWAYS
2CELLOS! You should listen to them! It's super cool :)