[Balintherlas]

I remember watching this movie based in the star wars univierse when I was a kid. I dont remember much, but I know there was this old guy with a white beard, I think he used to be a pilot for the rebels and he had a harpoon gun. I think he was helping these two kids but I'm not sure, I know there were these monster looking guys who were the bad guys, I think the kids were in a dungeon or had to get someone out of the monsters' dungeon. I specifically remember this one scene where the old guy, or maybe one of the kids or something, saw a group of monsters playing cards, then one of the kids or the old guy put a card up one of the monster's sleeve making it look like he cheated which then made all the monsters get in a fight. Does anyone know what the heck I'm talking about?