Celes saw the attack, and how that little spider was in the fight. She looked at it, then moved away, dodging a bite from one of the spiders. She then concentrates on her water magic, and then shoots it upwards, going and shooting it right in the middle of the group, aiming to split them all up with this. If fire would react like this, maybe water might work. Maybe washing them away might actually be useful here, but not by striking them all at the same time, but more like striking them to split them all up, to make it easier for the group to take care of them one at a time quickly. At least she hoped that would work... it was just a theory. Also, why else would they bring their young in battle here. They were all huddled up to protect that thing. So what would happen if they suddenly were to split up.
"I hope this works... if fire would react like that...wait... it did burn them when they were at the portal... so...." she says, thinking. Maybe they had something different here.