The room fills with smoke which sucks back into the jar. "I'll probably have to take you somewhere remote, where you won't be seen." you say, replacing the lid "Humans nowadays aren't used to seeing giant dragons"
"THAT WON'T BE A PROBLEM, MASTER" comes Sin-Garr's voice from within the jar "I CAN MAKE MYSELF INVISIBLE. I WON'T EVEN LEAVE FOOTPRINTS"
"Very well, we'll just go to the back yard instead."
***
Out the back you let the giant dragon out of the jar again (apart from his tail, of course) and he rises to a height of 60 feet "AHHHH, IT'S GOOD TO BE ABLE TO STRETCH OUT PROPERLY AFTER SO MANY CENTURIES!" says Sin-Garr stretching his claws out. "MASTER, I AM SO GRATEFUL THAT I WILL USE MY MAGIC BREATH TO TURN YOU INTO ANY FORM YOU LIKE."