Natsu manages to build up a huge amount of momentum by charging up his body with flames. He flies out from under Erza's boot, and zips around the room in a comedic fashion, until Erza catches him with one hand. She looks at the bug sternly, giving one of her famous frightening stares, and thinks, "Hmmm...this bug looks strikingly like Natsu"...she suddenly yells, to the surprise of the people around her, "You must be a bug trying to impersonate my guild members!!!...I will severely punish you for this!". Lucy comes over to ask what's wrong. "What's the problem Erza?". "This bug thinks it can outsmart me! I will give it the ultimate punishment, worse than death!" Erza then begins tugging at her boot. Everyone around her immediately put two and two together and backed up as far as they could go away from her, some even left the guild for the day saying, "this place is gonna reek for at least the next 2 days, let's get outta here!". Everyone covered their noses. Even Mirajane began to yell, "Erza! You don't have to do that! Please! Give the bug some mercy!". Erza yelled back, "Never! This bug deserves this." Erza finishes pulling off her boot, and out comes the most horrendous stench imaginable. Some people fainted despite having their noses tapped. When they were children, around 10 years prior, Erza would frequently air out her feet on a nearby table, much to the guild's dismay. One day, the smell was so bad, that the master forbade Erza from ever removing her boots. The smell that was released was the culmination of 10 years of foot stench building up, fermenting, growing, and waiting, inside of her boots. She brought the bug in front of her sole and began wiggling her toes furiously, "Listen little buggy, you're going in her for a LONG time, so get used to your new best friend!" She stuck Natsu to the bottom of her sweaty foot, and he simply stayed there. The foot sweat acted like the strongest adhesive known to man. She replaced her foot into the boot, and then sealed it up with the latches. She gave a good stomp on the floor, "there! now it will learn its lesson".
Meanwhile, inside Erza's boot, Natsu was dying...if only he could. He was inhaling so much foot stench, he was wondering why he hadn't passed out yet, and figured it must be something to do with the shrinking. The inside of her boot was soggy from foot sweat, and smelled disgustingly of cheesy feet, vinegary stench, a type of piercing smell that felt like it drove straight into Natsu's core. He tried screaming, and only ended up drinking foot sweat. Erza then decided to go on a mission alone.