OAHSIS (오아시스), formerly known as SEEART (씨앗), was a pre-debut seven-member girl group under KRAZY Entertainment. They were set to debut in early 2017 under Yama&Hotchicks Entertainment but was delayed. In 2018, Hyedam left and the group signed with KRAZY Entertainment.
The group's original name stood for "See, Always Remember Team".
Yama&Hotchicks officially formed the group after SuA, a former competitor on the show Produce 101, joined when they released a stage teaser of their project "Bloom the SEEART" after releasing a dance cover of members SuA and Hyedam, until finally, all the members performed together.
Every Saturday from October 29 to November 19, 2016, the group held a series of live streams on AfreecaTv to introduce the members and followed through their debut preparation. During the introductions, member Hyedam was not able to participate, the reason due to her age.
On December 12, 2016, they released the preview single "Bloom The SEEART". The title track "Cupcake" was produced by Ryan S. Jhun, who also produced "Dumb Dumb", "I", "Whatta Man" and "Crush". In 2018, member Hyedam left and the group moved to KRAZY Entertainment, also changing their name to OAHSIS.
|Hyeonju (현주)||Leader, Lead Vocalist, Visual||2016–2019|
|Chohyeon (초현)||Main Vocalist||2016–2019|
|Sua (수아)||Main Dancer, Rapper, Vocalist||2016–2019|
|Joa (조아)||Lead Dancer, Rapper, Vocalist||2016–2019|
|Yeeun (예은)||Lead Dancer, Vocalist||2016–2019|
|Hyedam (혜담)||Vocalist, Maknae||2016–2018|
- "Bloom The SEEART" (2016) (pre-debut)