Ekans

I toss the ball into the room and it opens half-way, right down the middle, and a white light spills out like a fluid and morphs into a huge creature. Huge for me that is, but of course it only seems that way because you're so tiny. It seems that whatever technology these pokeballs are made of they protect its content from the effects of the shrink ray.

The pokemon is woman whose upper body is that of a pale woman with thin waist, and the lower body of the tail of a purple snake. She has a white tanktop, with a necklace of chains attached to a silver symbol of a single eye and purple hair is messily tied to a pair of pigtails. Her eyes are golden with vertical pupils so thin that it looks like they've been slashed with a knife.

"Hey master! Ekans is here for your service!" she makes a peace sign and winks, before she notice I'm nowhere to be seen. "Master? Where are you master?" She looks around with a confounded expression, "Maaaaaster!" She looks left and right, up and down, high and low and slithers around in a circle looking for the one who summoned her.

At that point I whistle to get her attention. "Over here, Ekans." In an instance she jumps towards the grate and looks at me with a bright smile. "MASTER!"

"Ssssh..." I hush. She really does get excitable during night. "Oh, sorry master" she whispers, now worried her loud voice might have woken someone up, "But look at you, you're so tiny. Awww, poor little master is so frail and ****..." she says endaringly looking at me with her predatory eyes. "Well nevermind about that. Can you just get me out of here now?" As I say this the snake girl's tail rises, the very tip shaped like a hook for the occasion. "Of course, master. All aboard the Ekans express!"
I hold on to the tip of her tail, letting her manuver it towards her outstretched palms where she let me land.

"Good job, Ekans. Just whatever you do, don't drop me." I tell her very sternly. "You got nothing to worry about master. I'll hold on to you like you were my dearest prey." That... wasn't exactly comforting, but I let it slide. For now we got a job to do.