After swimming away from the grindylows, Arabella-Marie could still see the chest but she could see that there were more grindylows lurking below her and plus this part of the lake was dark she went up to the surface and took a deep breath while on the surface of the lake she cast the bubble head charm so make breathing deep down a bit easier and saw that the grindylows were coming after her still and she swam faster towards the chest and cast lumos to see where she was going and saw that there was more than just grindylows trying to distract her from her task ....