Familiars have half my max HP. What happens when I polymorph?

[TallerSpine]

A squishy wizard has a squishy familiar. Let's say the 10th level wizard has a Con of 10. He has at most 40hp. His familiar has at most 20hp. He polymorphs into a cave troll. Now his Con is 27. He gains 80hp. His max hp goes up by 80hp. Does his familiar gain 40hp?

On a similar topic, what happens if he is Con drained. Does his familiar similarly lose HP?

[Zaq]

Polymorph inherits the “your HP doesn’t change” clause from Alter Self.

The CON drain problem (or, for that matter, the problem with effects that INCREASE your CON and that don’t have a clause like Alter Self’s) is a weird edge case that likely doesn’t have a satisfying RAW answer. You can make an argument that any time the master’s max HP changes, the familiar’s does too (it IS a magical critter bound to your essence, after all), but that feels weird and fundamentally wrong, even if it’s plausibly RAW.

[Venger]

Polymorph inherits the “your HP doesn’t change” clause from Alter Self.

The CON drain problem (or, for that matter, the problem with effects that INCREASE your CON and that don’t have a clause like Alter Self’s) is a weird edge case that likely doesn’t have a satisfying RAW answer. You can make an argument that any time the master’s max HP changes, the familiar’s does too (it IS a magical critter bound to your essence, after all), but that feels weird and fundamentally wrong, even if it’s plausibly RAW.

yeah you retain your own hit points.

in practice for the most part, your familiar has half your hit points when you're just kind of hanging out. I've never seen anyone say your familiar gets a boost if you use vampiric touch or flip on an amulet of tears or cast bite of the werex.