Blue (status effect)
From the Super Mario Wiki
Blue is a status effect in Paper Mario: Color Splash, inflicted only by blue paint in the battle with Roy. While Mario is in this state, his head is covered with blue paint and he sits on the ground, turned away from the player, and looking saddened. The music also slows down and now consists of a sad piano song. While under this status effect, Mario can only use cards with blue backgrounds. Like all other status effects exclusive to said battle, the effect is temporary and only lasts one turn.