This is Rocket Slime, From Dragon Quest Heroes: Rocket Slime. He is a slime from the kingdom of Slimenia. He is also a master of the Elasto-blast and the driver of the Shleiman tank.
I've been playing this game for the past couple of days, and, while I admit it's quite a rediculous idea, It would be fun to see happen.
What would he do? Well, he would wield the various items that get used as ammunition in the schleiman tank o'course, That means Boulders, bombrocks, Various swords(From small to Rediculously large), Chests, Shields, The sun, etc. He would also use the Elasto-blast to good use, perhaps as his neutral or foreward-B attack. His Super Smash is easy. The Schleiman tank appears and rains destruction down on the hapless combatants.
Silly idea, but an idea that has not so far gotten it's own thread.
Also, fun fact, in Japan, Dragon Quest is CRAZY popular. The government had to mandate that no Dragon Quest games are allowed to come out on work days, because the economy would grind to a halt from everyone skipping work/school to buy and play the game. So, on the scale of chance of all the unimportant cute things, Slimes(The DQ cute things) are comperable to Moogles and Chocobos.
