It is currently unknown how, but at one point grey puffles were cursed to turn to stone. Grey puffles were trapped as statues for many years, and eventually freed and returned to normal when the sakura trees began to bloom.
They were first revealed in issue #103 of the Club Penguin Times that grey puffles were once cursed and turned into stone.
Its training dummy is loosely based on the Sandbag from the Super Smash Bros. series.
Their attacks on the training dummy are also based off of moves from the Smash games, such as the spinning cane attack being inspired by Link's B-Up.
The animation when a grey puffle eats a cookie references Sonic's Spindash in Sonic CD.
The animation of when the grey puffle dances is vaguely based of Stu Jr's dance animation.
They were originally going to have a slightly different tongue color and the training dummy was going resembles a walrus and a polar bear, but was changed to resemble Octi.
The bathing animation was also originally just going to be the grey puffle bathing in a square bathtub with a paper screen behind them, but was changed to incorporate the gardening aspect of the puffle.
Their angry animation also originally had the grey puffle hissing, but was changed to it reading a newspaper instead.