If you spend too long grinding MP, the game gives you less and less MP. Why? Because it's cowardly to stay in one spot and grind until you're overpowered. The game is essentially calling you out for not being manly enough to face the challenges ahead.
Why does SpongeBob not have the "bubble" aspect of his attacks from Battle for Bikini Bottom? 2 reasons:
He's trying to be more manly, and, according to the Thugs, bubbles are babyish.
Bubbles wouldn't affect living creatures, which a majority of the enemies are. The robots from the latter game would short circuit from the bubble soap.
The enemies in the Thug Tug give you the most MP out of any enemies. Why? It's because they are the manliest thugs in that side of the sea, so you'd have to be extremely manly to beat them in the first place.
