Snake nods, "'It will be a big help,' says Ayn." He hesitates for a moment, but then moves in closer to Marinette to ask softly, "Call my vessel name?" If nothing else it would be strange to ask for that while using either Ayn or Martin's name. Not when it's something he finds to be so personal.

He knew that his vessel form would give him an edge in trying to find an animal. While he might only be dichromatic as a giant snake, he was more sensitive to UV light, could sense heat, movement on the ground, and a host of other advantages in finding prey that he didn't have as a (mostly) human. Of course, this time at least it's not prey he would be eating.

He's already putting Martin with Marinette and Ayn with Adrien. Firstly, he's pretty sure Marinette wouldn't refuse him asking to be his vessel form, but perhaps more importantly he wanted Ayn as far from Marinette while he's in his vessel form as he can get her. Ayn is far chattier than Martin, and her favourite topic happens to be Snake's (possible) love-life. They'd already had an incident back in the forest, and he's not too keen on letting Ayn try harder to convince Marinette about how Adrien feels about her, let alone how Snake feels about anyone romantically. Not after how well that went last time.