Because, when he has a toad familiar, he likes to introduce it. To everyone. And strap it to his hat, so it can ride in comfort. And use Magic Mouth to make it talk. For some reason, only the toad brings out this particular silliness.

I'm not allowed to bribe another player into making twelve consecutive suicidal half-dragon ogre characters just so my necromancer can turn their bodies into really awesome zombies.

The set of all hydras and the set of all zombies may never have any overlap whatsoever. Ever. This applies to everyone.

Maybe he has been watching This a bit too often.

A ninety-foot sword does not grant ninety-foot reach.

Even if the rules allow it, I am not allowed to have a mermaid with a land speed exceeding that of a horse.

I'm not allowed to found a mobile orphanage for the sole purpose of having the little brats carry my stuff.

After convincing the DM to allow the mobile orphanage, I'm not allowed to create more orphans after the first lot gets eaten.

My Changeling will not use Minor Change Shape to make major NPCs appear to do highly embarrassing things in public, no matter how funny it would be if the lovely, stuck-up high prefect were to walk into a random pub and do a strip tease.

The same applies to mimicking PCs.

No, the Cleric is not now legally married to that barmaid.

It is frowned upon for my Changeling to shapechange into the queen in order to bear the king's child and thus become technically sexless parent figure to the legitimate heir to the throne until the DM has at least a month to decide how the Hell that plotline would even go down.

Using Polymorph Any Object to permanently turn a kobold into a great wyrm red dragon makes baby Jesus cry. Pointing out that Share Spell lets me do the same to my familiar resulting in a godly dragon with a godly dragon familiar will make the DM go into cardiac arrest.

I'm not allowed to yell "Blitzkrieg!" and sweep all the pieces off the board and declare myself the winner.

When playing an unintelligent character I am not allowed near alchemical agents of any sort.

I am not allowed to incite Global Riverdance Hour ever again.

I am no longer allowed to play a character named Bob.

Or named Bob even though it is spelt backwards still makes it Bob.

Or a character that was named Bob that now is called Exbob.

And by any ruling, at anytime am I to not play a Rancor named Bob even if it is spelt with an alien alphabet.

But I can still play a Guy named Sue.

Did Bob do something naughty?

A glass armonica is not a reasonable instrument for an adventuring bard.

"Silvia," "Roland," and "Aegis" are indeed acceptable names for my character's weapon. "Mr. Happy" is not.

Yes, being constructs, Warforged can use Alter Self to turn into animated objects. No, clothing is not an acceptable animated object type, no matter how much of an advantage in espionage it may be to turn into the prince's underwear.

An animated Necronomicon is not an acceptable form, either.

Or an animated shotgun.

Or an animated Ring of Three Wishes.

My warforged may not use Alter Self turn into a highly respected reference book in the local library only to bludgeon the first scholar to try and use her half to death.

I am preemptively banned from playing kender or even playing in the same world as kender.

I cannot cast Gate to summon a kender from another world. Nor may I use True Mind Switch to steal said kender's body.

I may not use True Mind Switch to steal any major NPC's body.

Or a dragon's body.

Or any big creature the DM pulls out to scare us.

Hill Giant Ninja is not a valid character concept.

Nor is Troll Imagist.

Nor is a Slaadi Monk.

Nor is an Angel Ravager.

That still doesn't mean I'm allowed to kill the guy who's allowed to play a friggin' Drow Paladin. So not fair.

Flirting with other players, quoting Urban Dictionary, sex, and yelling at onlooker are looked down upon by my group.