The chaotic mana gathered around Envy immediately. It was clear that the taunts the group had made already sat within Envy's mind to constantly wear away at him. But now, he was finding that his slime body was being easily beaten.
Every time he adapted the tentacles to use different elemental slime forms and attacks, he was countered or faced a perfect defense. It made him feel that he was not at all gaining what he had come for. He didn't even see a single sign of the brilliant slime any more.
That alone, he also noticed that there were roars of dragons nearby. Not to mention that the slimes he had sent in to murderous rage nearby, were being killed faster and faster. Hundreds of his bred slimes destroyed in minutes.
Creation is hard, cheer me up!