Rumors had spread of the "blue poo." Basically an abused boy had run away into this forest and survived on some of the bugs and plants he had found. When authorities found him he got the help he needed but within days he began changing and once a week had passed he was indistinguishable from the boy he once was. Doctors found a bacterial infection in his intestine synthesizing a number of prohormones and causing an alarmingly vibrant blue color in his poo. He was given antibiotics and was fine although was left with the body of a balding adult body builder despite being 13. Rumor is he had eaten handfuls of blue colored larva over the couple days he was on the run which is where he contracted the mysterious infection.
Being a scrawny 15 year old, a little help in the manliness department doesn't sound bad at all though you don't want to end up looking like you're in your late 20's like that kid... and a dramatic overnight change wouldn't suit your tastes either.
That's why you had a plan... Find one bug, eat it, watch for evidence of the infection, and monitor changes closely. Once you can pass for a well developed Junior or Senior. Tell your mom about your poo being weird, go to the doctor, get antibiotics, then have an amazing life with a dream bod...
After exploring for a couple hours, turning over rocks and rotten logs, you found plenty of weird bugs, plants and fungi, Eventually you found what you were sure must be what the rumor spoke of, a semi transparent grub or maybe maggot, with blue insides. it was on a tree with blue moss/lichen, feasting happily.
You easily plucked it off the tree and hesitated unsure if you should chew or swallow it whole... you eventually decided to swallow it whole hoping not to taste anything and not vomit it back up. Like a gross vitamin you popped the tiny blue worm down the hatch and quickly turned to go back home.