Your indoor pool suddenly filled with slime. Touch it if ya like.

Permenant protogen suit that once worn turns you into a protogen. One side effect is that you will now gain weight much easier.

You were put into a room that is made to fatten you with slime.

An anthropomorphic fox that you own as a pet. She does whatever and has the ability to make you fat by rubbing your belly.

A spice bottle made to make people fat. Just put it on food and you're good.