Synthesist Eidolon that becomes too small for it's master

[Winterwalker]

I see that a synthesist needs to have an Eidolon that is at least as big as he is, however what happens to a characters eidolon when he grows larger through class features (permanent size increase.)

He dips into summoner and it's legal at the time because both summoner and Eidolon are medium sized. But the summoner later takes a class that has a size increase feature that makes him large sized. Can he still summon his Eidolon? What would happen?

Can't find an answer for this one.

[ShadowcatX]

I would probably rule that he can no longer summon his eidolon at all. If I thought this wasn't an attempt on his part to game the system, I might offer im a one time conversion to a normal summoner.

[Theconiel]

I have to agree with ShadowcatX on this one. But he can still do all the other things he gets from his dip - notably Summon Monster SLA and spells.

[Rogar Stonebow]

Just make him change his evolutions to include size increases to eidolon to match that of his character.

[Vincent Takeda]

Codpiece Eidolon?