Fun fact: this page used to be static. It didn't cross my mind that maybe, people needed to know what the spells were used for. Now I know better, and this is what I came up with.
Panel 1: Large view of the bottom of the amphitheater from the point of view of Oscar and Valentin. The teacher opens suddenly the door, shouting a spell (written in archaic latin), a cat entering at the same time "luces propinquate et lambite manum meam (translated: Lights, come lick my hands)". Oscar says "Wh- oh noo...". Valentin adds "Again?"
Panel 2: The room is filled with darkness, with only the teacher brighly lit from the stolen lights in her hands. She seems to enjoy herself. Oscar is annoyed, muttering "I need light dammit".
Panel 3: Oscar looms over his writing, casting a purple spell. On his arm is his rat. Some colored tendrils come from him. As Oscar says the spell "lux... appare... te rogo (translated: light, appear, i beg you)" a bright light appear on his palm...
Panel 4: Oscar is rather proud of himself, but the light suddenly flees away from him. The teacher says : "Well tried... but not clever enough!"
Panel 5: Oscar is outraged and shouts "Ma'am!"
Panel 6: Oscar leans back, arms crossed, grumbling "I hate when she does th-" before being interrumpted by Valentin, whose hands slam on the desk.