Regardless of how reasonable or not Aurelie's protests may be, the little bugs open up on the girls and their companions with multiple sprays of thick, sticky silk strands. Harmless as wild pokémon responses go, but they're going to get pretty heavy if they keep piling them up.
Arrangement: The wild pokémon are perched on two trees to either side of you, one of each species on each tree. They're close by as Aurelie walked straight into their net.
Initiative order:
Caterpie 1 - 15
Caterpie 2 - 10
Lisette - 10 (9)
Aurelie - 10 (9)
Sewaddle 1 - 4
Bic - 3 (2)
Sewaddle 2 - 2
Marshmallow - 1 (1)
Both caterpies go first and unload a String Shot each. As a Cone 2, they cover Aurelie and Lisette plus the mons riding on top of them.
String Shot (AC 3 - Speed evasion applies) (1d20=5, 1d20=2) (http://invisiblecastle.com/roller/view/4483853/)
This means the second misses all and the first hits all, applying -1 Speed combat stage (*0.875).
Accuracy - Ember (1d20=17) (http://invisiblecastle.com/roller/view/4484680/) vs AC 2+Special/Speed Evasion
Targeting Caterpie 1, rolled damage (2d6+8+10=27) (http://invisiblecastle.com/roller/view/4484682/). Subtract Sp. Def. then multiply by two because it's super effective.
Unfortunately for it, it just passes through the glow surrounding the ghost candle and pulls a faceplant landing on the soft ground.
Bic's ember, meanwhile, hits one of the caterpies square in the face just as it seems to be preparing either for another salvo of silk or to run away, it's hard to tell. And a moot point in any case, as the hit leaves it reeling with the closest thing to swirly eyes it can pull off before it drops off the tree trunk the short distance to the ground, knocked out clean.
The other sewaddle is unfooled by Marshmallow's cuteness, and attempts the same maneuver the other did, only to sail clean over the cleffa's head and faceplant much the same as the first did.
The caterpie still left standing (crawling) wiggles its antenna furiously at the two landed sewaddles. Maybe it's the ringleader in this whole mess. It blows another spray of sticky silk onto the girls and their pokémon and starts crawling up the tree to put some distance between itself and the fire-type.
Sewaddle 1 tries to use Tackle on Bic and finds out that Ghost-types are immune to Normal moves.
Ember hits and KOs Caterpie 1 in one hit.
Sewaddle 2 uses Tackle on Marshmallow...
Tackle! (1d20=3) (http://invisiblecastle.com/roller/view/4484733/)
...And misses.
Charm hits, Sewaddle 1 has its Atk reduced by -2 CS.
Caterpie 1 is out of the running.
Caterpie 2 uses another String Shot and crawls up the tree for cover and distance.
String Shot (AC 3 - Speed evasion applies) (1d20=3) (http://invisiblecastle.com/roller/view/4484748/)
And misses anything with more than +0 Speed evasion (Looking at you, Bic and Marshmallow - not that it matters, for them).
Back around to Lisette and Aurelie.
Initiative order:
Caterpie 2 - 10
Lisette - 10 (9)
Aurelie - 10 (9)
Sewaddle 1 - 4 -2 Atk
Bic - 3 (2)
Sewaddle 2 - 2
Marshmallow - 1 (1)
Astonish (1d20=14) (http://invisiblecastle.com/roller/view/4484794/)
One short of a flinch, but that probably makes the grade regardless of the Caterpie's evasion.
Damage (1d8+8+6=15) (http://invisiblecastle.com/roller/view/4484795/) minus Defense.
Bic, meanwhile, surprises the retreating caterpie with a poke on the nose, causing it to jump off the tree with another spray of silk and land on top of Aurelie in her struggles with the webbing.
Sewaddle 1 tackles Marshmallow
Tackle (AC 3, Physical or Speed evasion applies) (1d20=17) (http://invisiblecastle.com/roller/view/4488571/)
And hits for Tackle damage (DB 4, +9 Atk) (1d8+15=18) (http://invisiblecastle.com/roller/view/4488574/)
Bic hits Caterpie 2, and it remains standing.
Sewaddle 2 Tackles Marshmallow as well
Tackle (AC 3, Physical or Speed evasion applies) (1d20=16) (http://invisiblecastle.com/roller/view/4488576/)
And hits for Tackle damage (DB 4 +7 Atk) (1d8+13=16) (http://invisiblecastle.com/roller/view/4488577/)
Marshmallow Encores Sewaddle 2, and it's Suppressed.
Caterpie 2 shoots more string at Bic and jumps on Aurelie's face.
String Shot (AC 3, Speed evasion applies) (1d20=17) (http://invisiblecastle.com/roller/view/4488587/)
Initiative order:
Caterpie 2 - 10 -10 hp
Lisette - 10 (9)
Aurelie - 10 (9)
Sewaddle 1 - 4 -2 Atk
Bic - 3 (2)
Sewaddle 2 - 2 Suppressed
Marshmallow - 1 (1)
Bic indignantly hiccups up another puff of embers at the other Sewaddle.
Capture vs. AC 6 (1d20=3) (http://invisiblecastle.com/roller/view/4488673/)
Not going to bother with the capture roll!
Ember Accuracy (1d20=13) (http://invisiblecastle.com/roller/view/4488674/) vs. AC 2. Special/Speed Evasion applies.
Fwoosh (2d6+8+10=22) (http://invisiblecastle.com/roller/view/4488675/), minus Sp. Def. but before type vulnerability.
Meanwhile, the sewaddles continue going after Marshmallow, one of them crawling up Lisette's leg only to be flung off by Bic's puff of fire, the other meeting her charge with a spray of silk in confusion, which doesn't keep it from getting slapped.
Lisette's ball hits, but the capture roll fails. Aurelie's ball doesn't even hit.
Sewaddle 1, being unsuppressed, Tackles Marshmallow
Tackle (AC 3, Physical or Speed evasion applies) (1d20=2) (http://invisiblecastle.com/roller/view/4489575/)
And misses.
Bic's Ember hits. Sewaddle 1 takes massive damage... but is still standing (barely)!
Sewaddle 2 is suppressed and so sprays strings again.
String Shot (AC 3, Speed evasion applies) (1d20=19) (http://invisiblecastle.com/roller/view/4489576/)
And hits Marshmallow and Lisette.
Caterpie 2 String Shoots Aurelie again
String Shot (AC 3, Speed evasion applies) (1d20=18) (http://invisiblecastle.com/roller/view/4489593/)
And hits.
Initiative order:
Caterpie 2 - 10 -10 hp
Lisette - 10 (9) -2 Spe
Aurelie - 10 (9) -2 Spe
Sewaddle 1 - 4 -2 Atk, as in the red as it gets
Bic - 3 (2) -2 Spe
Sewaddle 2 - 2 Suppressed
Marshmallow - 1 (1) -3 Spe
Down+B AC 6 (1d20+1=2) (http://invisiblecastle.com/roller/view/4489795/) haha nope
Ember AC 2 (1d20=9) (http://invisiblecastle.com/roller/view/4489822/) targeting Sewaddle 2
Burn baby burn (2d6+8+10=29) (http://invisiblecastle.com/roller/view/4489827/)
With the attacks apparent ringleader captured, the two sewaddles seem to decide that caution is the better part of valor and turn tail to start crawling back up into the trees, but not before Bic's ember hits the unwounded one, prompting it to instinctively curl up in the leaf it's wearing. Just as it uncurls and continues fleeing, Marshmallow is upon it and knocks it out with a slap.
Lisette successfully captures Caterpie 2, complete with the 1 trainer XP for doing so.
The less said about Aurelie's throw, the better.
The sewaddles start crawling up into the trees.
Bic's Ember and Marshmallow's Pound both hit and knock Sewaddle 2 out cleanly.
Sewaddle 1 is the only one left standing with a sliver of health.
Your next line will be "fuck, not another natural 1!" (1d20=13) (http://invisiblecastle.com/roller/view/4496115/)
Capture roll (1d100-1=67) (http://invisiblecastle.com/roller/view/4496119/)
If this were a videogame, there would be a catchy little capture tune playing now. But it isn't, so there isn't any tune, because there's no speakers in the forest. Don't be silly.
The final question now is whether bug silk leaves stains in clothing.
Caterpie: Level 5, Rash nature (+SpA, -SpD). Shield Dust ability.
Sewaddle: Level 5, Naughty nature (+Atk, -SpD). Leaf Gift ability, currently set to Sturdy and Overcoat.
Aurelie and Lisette also get 10 XP each to divide among their pokémon.
Aurelie, being the cook of the team, knows it is indeed the season for a specific, quite expensive sort of medicinal mushroom that's also considered a delicacy. It only grows on paras, the pre-evolved form of this man's pokémon.
Intuition or Pokémon education for more.