Jesper is gifted the tools for worm grunting
I've been rewatching Charborg's VOTV streams, and he mentioned worm grunting, which I forgot even existed. I immediately thought about how Jesper would be over the moon to know he could just summon handfuls of worms whenever he wanted. I originally considered that it would be something Yarrow knows how to do, just, because he's been alive for a good chunk of time (and maybe he does know, I don't doubt it!), but I really enjoy the idea that it could be gifted to Jesper from the wild imps.
By this time, the wild imps and Jesper are familiar, Jesper is bonded with Sol and Kena, and Kena has begun to openly show affection towards Jesper, even he's still a bit reserved and hesitant about it. Jesper has probably helped them a lot with learning more about the plants and food sources in their area, probably gifted them blankets from Yarrow, and the imps are wanting to give back. I'm sure they'll find something more specific for Yarrow, but anyway...
My idea for a gift for Jesper was that Kena and Sol (and most likely the other bond they're close with), are out and a fisherman is off in the distance. Kena, specifically, watches this man cut grooves into a stick, and use a secondary stick to rub together over the notches, and summon a bunch of worms from the ground to use as fishing bait.
Wild imps already dislike the presence of "persons", as they call them, and will typically antagonize and steal from them. But, I like to imagine Kena is a bit more hands-off this time, and just simply steals the sticks when the fisherman isn't aware.
Wild imps do use tools, but I don't think worms are of much use to them, especially when if they wanted a fish, they could just, fly up and grab it from the water much like a bird. Fishing is a person thing to do. They might garden to a small extent, so worms could be beneficial in that way, but I think they'd just, take whatever Jesper gifted them and throw them in their gardens, rather than doing it on their own.
Anyway, Kena would test it out until he figures out how to replicate worm grunting like the fisherman did. Next time they're hanging out with Jesper, Kena tells Jesper he and Sol have a gift for him.
Kena: "Jesper, has gift for you."
Jesper: "Has gift for imp?"
Sol: "Yes!"
Kena unveils two sticks, and hands them to Jesper. Jesper opens his eyes and is already thrilled with the gift as is.
Jesper: "Is stick! Hehehe---loves stick! Thanks imps!"
Kena: "No, is for worms, like Jesper likes."
Jesper peeks at Kena through one eye, head tilted in confusion.
Kena: "We saw a person use to find many worms. Figured it out, and will show imp how to use."
Jesper: "Many worms?"
Sol: "Yes! Fisherman had handfuls!"
Jesper: "PLEASE TEACHES IMP! JESPER BEGS! HEHEHE! PLEASE TEACHES JESPER TO BRING MANY WORM FROM DIRT!"
Sol grabs at his hands in an attempt to calm him down. Kena laughs.
Jesper: "INDEBTED TO IMPS! PLEASE TEACHES! Will bring many berries to imps!"