Yep, according to Starship Entertainment, their two groups Monsta X and Cosmic Girls will be combining to create a new group called Y TEEN.
Y TEEN consists of all seven MONSTA X members as well as seven Cosmic Girls members (Exy, Cheng Xiao, Eunseo, SeolA, Soobin, Yeoreum, and Dayoung), resulting in 14 members total.
Here's Cosmic Girl's "Catch Me"
and Monsta X's "Rush"
They've already been on some variety shows together where Monsta X lost their minds over Cosmic Girls' insane dancing skills:
WHO IS READY?!