5 Seconds of Summer's Rock Out With Your Socks Out Tour kicked off on May 4 and on tour with the Aussies is their first signee, Hey Violet, to their label Hi Or Hey Records.

Michael Clifford Dyes Hair All Black While On Tour

The two bands have begun a prank war, which is essentially a rite of passage while on tour.

The Hey Violet band members kicked off the prank war on May 11 when they hilariously taped a photo of their lead guitarist Casey Moreta to the inside of a toilet the 5SOS guys were apparently using.

Ashton Irwin Tells Dublin Crowd To 'Rock Out With Your Shamrocks Out'   

That prank allowed them to take the lead in the prank war.

The Aussies fired back though just days later with what looks like pieces of bread and flipping over tables and chairs in the Hey Violet dressing room.

The Hey Violet band members promised 5SOS "they've got another one coming."

Hey Violet's drummer Nia Lovelis told 5SOS "well played" on Twitter from their silly prank.

Since then things have been quiet in terms of pranks, but Friday the California band pranked 5SOS yet again. The Hey Violet drummer teased a photo of herself blowing up balloons while captioning it with "y'all are in for a surprise."

yall are in for a surprise A photo posted by Nia Lovelis (@nialovelis) on May 29, 2015 at 1:52pm PDT

Her bandmate Moreta then shared two photos of what they did to the 5SOS dressing room. Balloons filled it and cups filled with most likely water were lined on the floor too.

"[L]eft the guys a little present tonight..." Moreta insisted.

The 5SOS guys took a video of themselves dealing with the liquid-filled cups on the floor. They did not seem pleased.

Calum Hood is seen tossing their bags over to Michael Clifford and Luke Hemmings whom are both standing on top of a couch.

Unfortunately Hood and his bandmates were not able to prevent spilling some of the cups. Hood tossed a sweatshirt and Clifford wasn't able to catch it so some cups tipped over and spilled out.

While the cups prank was not appreciated, Hood, Clifford, Hemmings and Ashton Irwin seemed to love the balloons a bit more.

"I actually enjoy this," Hemmings said in the second video while Irwin said, "This is fun!"

Hood made it clear they'll be getting them back since he said, "Just wait" repeatedly. Irwin even mentioned something about involving alligators, which he even tweeted Moreta about.

Lovelis revealed that 5SOS' retaliation would surely "be brilliant," which Clifford confirmed.