Slime Morimori Dragon Quest is a new GameBoy Advance action-RPG adventure starring slimes, the Dragon Warrior/Dragon Quest mascot.
A blue slime seems to be the main character, with other DQ/DW monsters thrown into the frey.
Some of the moves that the slime can perform are: Stretching to 3x the normal length of the slime. Rolling, he can roll around the map, also he can gain speed and collide with enemies on the screen. And multiple slimes can stack up and hop around the screen together.
There seem to be multiple variations of slimes, standard Slimes, King Slimes, and Healers, apparently there are also baby slimes with bows on their tips.