Manifest's page

I'm a GM and one of my players (an Alchemist) asked me a question. If his Tumor Familiar is fused to him and he drinks his invisibility extract, does the Tumor Familiar turn invisible too? Or does it just appear to hang lamely in the air while the alchemist is invisible. My gut tells me yes and I've made other inquiries to back it up but I wanted other opinions.

But here's the broken part:

This player came back next week and asked, if a character has an Imp Tumor Familiar (by virtue of the Tumor Familiar Discovery and the Improved Familiar Feat) and it is attached to him, can the Imp cast its At-Will invisibility and make itself and the Alchemist invisible.

While this won't ruin the campaign (a surprising number of monsters have see invisibility) I would like to find out whether this is actually possible because it could get inconvenient to have the party Rogue multiclass alchemist for invisibility whenever he wants.

First time posting anything, so I might be posting in the wrong place. Forgive me if I am.

Anyway, my question is this; when an alchemist is fused with his tumor familiar, how do spells/spell-like abilities affect them? to be more specific, if the two are fused and the alchemist drinks his invisibility extract, do they both turn invisible? Or is the alchemist invisible while the familiar appears to hang in the air?