How say: "I will get you back for that prank!"?
As in payback. "I will prank you back." Or: "Be carefull for the payback." Or: "You got me, but I will pay you back!"
Saludos
A native just told me that it is something like: "me las cobrare". Meaning: "I will pay them." Supposing somebody made a prank on you, you could say something like: "lo lograste." ("you did it/ succeeded"). "Me las cobrare." ("I will pay them/ I will charge them")
7 Answers
How about: ajustar cuentas?
¡Ya te ajustaré las cuentas!
The answer is in the title of this song
que te perdone Dios por que yo no, (Is that meant to be por qué or porque? if it's porque then this is my kind of song).
May God forgive you because I don't ????
Esto no es una cancion mira mami es una maldicion
I believe the correct wording would be "I will get back at you ...", in any case, it is obvious that this is parallel to "I will return the favor ..." There is (or should be) no implication of revenge being taken when one's back is turned but I would be careful about that, myself! 
"get you back" is very idiomatic. Add to the dozens of uses of "get" in English, and I would guess there's no direct translation.
The English did not explicitly say, "I will take my vengence on you". So "Tomar venganza de uno" may express the concern, but it loses the flavor.
I'm hoping a native will throw in idiomatic expressions. They would not be direct translations, either, but perhaps communicate with a similar and familiar jargon.
How about just:
¡Cuidado!
Watch out!
payback (definition 2)
Tomar venganza de uno -> to take vengeance on somebody
to play a prank on somebody -> gastarle una broma a alguien
Trying to combine them.....Tomaré mi venganza de ti por gastarme bromas pesadas.
Not a native. Just a wild guess. Wait for a native or someone that isn't guessing.
