No, It's a Yo-Yo!

From Mafalda, which can be your introduction to el voseo:

"What the heck is that Felipe?" "A yo-yo."
"A you-you?" "No, a yo-yo!" 

"Ah…a Felipe-Felipe?" "No, it's not yo like me!  It's called a yo-yo! Do you understand? 
Yo-yo! Yo-yo!" 

"Self-centered!"

Notes: 
Vos is used instead of tú most famously perhaps in Argentina, but also in other parts of the Spanish-speaking world.  It has its own fun conjugation rules as well.