Try Not to Flinch Challenge!!!! OMG!!! this was harder than we thought!!! The Spider Box was the most SCARY! Do you think Ronald flinched on Jack in the Box? Subscribe for more cool videos! SIS vs BRO instagram @ sisvsbro_karina_ronald Karina has a new instagram @ kurzawa_karina Ronald’s new instagram @ ronaldkurzawa NEW MERCH: https:// Welcome to SIS vs BRO! This is where Karina and Ronald join forces to challenge each other in countless fun videos! Challenges, gaming, and more!!! Be sure to SUBSCRIBE and we will see you in the next video!!! Facebook: https:// We LOVE you guys!!!