▁ 1 0 ▁and ▁on ▁June ▁ 1 3 , ▁J elly fish ▁Entertainment ▁revealed ▁that ▁G ug ud an ▁would ▁be ▁a ▁nine - member ▁group . ▁On ▁June ▁ 1 7 , ▁J elly fish ▁Entertainment ▁announced ▁the ▁group ▁name . ▁ ▁On ▁June ▁ 2 2 , ▁the ▁group ▁confirmed ▁that ▁they ▁were ▁going ▁for ▁a ▁" mer ma id " ▁concept . ▁Following ▁the ▁announ cement , ▁a ▁highlight ▁med ley ▁of ▁the ▁group ' s ▁debut ▁mini - album ▁was ▁released ▁on ▁June ▁ 2 4 . ▁They ▁deb uted ▁on ▁June ▁ 2 8 , ▁ 2 0 1 6 ▁with ▁the ▁mini - album , ▁Act . ▁ 1 ▁The ▁Little ▁Mer ma id , ▁with ▁" W onder land " ▁as ▁the ▁title ▁song . ▁Their ▁debut ▁show case ▁was ▁held ▁at ▁the ▁Yes 2 4 ▁Live ▁Hall ▁on ▁the ▁same ▁day ▁as ▁the ▁album ' s ▁release . ▁ ▁G ug ud an ▁participated ▁in ▁J elly fish ▁Entertainment ' s ▁annual ▁winter ▁project , ▁J elly ▁Christmas ▁ 2 0 1 6 , ▁with ▁their ▁label ▁m ates ▁Se o ▁In - gu k , ▁VI XX , ▁Park ▁Y oon - ha , ▁Park ▁Jung - ah , ▁Kim ▁Gy u - sun , ▁Kim ▁Ye - won ▁and ▁Ji y ul . ▁The ▁title ▁track , ▁" F alling ▁() " ▁was ▁released ▁digit ally ▁on ▁December ▁ 1 3 , ▁ 2 0 1 6 . ▁▁ 2 0 1