What happens when a spellcaster attacks his own summoned or animated monster? Does the monster flee, fight back, just stand there and look stupid, or something else?
Assuming 2nd or 3rd Edition, I believe the answer is ‘whatever the spellcaster wants it to do’. It’s not a charm or compulsion, attacking the creature doesn’t free it from the caster’s absolute control.
So couldn’t a Chaotic Evil spellcaster simply summon monsters at whim, then kill them for the XP?
Any dungeon master worth his salt would disallow gaining XP in this manner. There are also familiarity rules in later editions, implemented by level difference. When you’re level 20 and you’ve killed your 10,000th orc, you aren’t going to gain much XP by killing the 10,001st.
I’d make the argument that you’re not becoming any more experienced by killing a defenseless summoned creature.
Then if the party wanted to argue why they’d keep xp for killing monsters under a Sleep, Hold Person or similar, I could offer to disallow that as well.
Summoned monsters explicitly don’t give xp. Or loot, since they disappear immediately.
As others have said: No challenge, no XP.
Unless they were summoned with the spell Gate, I think. That spell operates a bit differently because the monsters you summon are so powerful you usually have to cast protection spells just to prevent them from turning on you.
Gated creatures aren’t Summoned. 
And Summoned creatures don’t give experience. It’s not even the lack of challenge (which should nix the XP gain anyway); summoned monsters NEVER give XP. Even if an evil wizard summons them to kill you. You get XP if you beat the wizard, but the ability to summon monsters is considered part of his CR.
On the other hand, if the party wants to kill their wizard and his summoned creatures, you can give them some XP (depending on how much of a pain in the ass the Wizard’s player is being about trying to scum free XP).
Summoned creatures don’t really exist in the traditional sense. They are beings formed of magic and when killed they dissipate as any other spell would. Just as you don’t get XP for dispelling your own spell, you wont’ get XP for killing a summoned creature. And the creature being a direct creation of a magic spell, is fully under control of the being that summoned it. So it sits there unless told what to do.
And as someone said, gated creatures aren’t summoned. They actually exist outside of the spell. The spell just acts as a travel portal. So killing a gated creature will gain you XP since you are killing an actual preexisting creature or being. But no one’s really going to waste a high level spell slot like that as a convenient XP source anyway. Especially since you actually have to know what it is you want to gate. You can’t gate in random creatures.
Could you argue that you’d get xp for slaughtering said monster—literally, as in how a butcher slaughters animals? Or would you have to properly dress the carcass as well?
To paraphrase CandidGamera’s answer, and speaking myself as a long-time RPG Game Master, the correct answer is:
“Whatever the spellcaster wants it to do, and whatever the GM wants to happen as a result of that desire.”
An RPG, the only place this kinda thing might happen, is nothing more than grown-ups (usually) playing make-believe with a set of rules they all agree to. Those rules have no more ‘real’ permanence or authority than the rules to a game of Calvinball. Ultimately, the only rule should be ‘whatever makes a good story.’
So, speaking for myself, it would depend entirely on the situation, as to what would happen if a player’s character decided to attack her own creation. Some options are that the creature turns and fights, or it flees, or it disappears back to its original location/dimension/state of being/whatever, or simply ceases to exist, or begs for mercy, or really anything at all. The only limit is the imagination of all involved and the self-imposed limits of the story that is being told.
To put this a little closer to the answer I think you really wanted, here’s a few excerpts from the Pathfinder(D&D clone, kind of 3.75 edition) rulebooks:
Note that there are many ways to call a creature to you; this may affect the GMs decisions.
I, personally, would likely allow anything once, assuming it fit the story and the character. If it became disruptive, I would first find a way within the game to stop it or alter the equation to be MUCH less in the character’s benefit. If that didn’t work, I’d alter the story to make it impossible to continue, and if THAT didn’t work, I’d just tell the player to knock it off already or get out of my game.
Then I’d send evil undead zombie pirates after them… in the real world.
Bolding mine.
Mmm, no. It’s certainly a valid answer, but I can’t agree that it’s THE correct answer. Rules is rules, and if one insists the question has a singular correct answer, it must comport with those rules.
Obviously, you can run your games however you and your players like, but let’s not try to subtly indoctrinate the original poster with your gaming philosophy when he asked a rules question. He’s considered about what he saw as a potentially abusable loophole in the rules; those people who tell him ‘oh, the GM can use his authority to stop that’ are correct, but misleading - because the loophole doesn’t actually exist.
Well, if you accept that words printed in a rule book are “THE” rules…
So, unless something can be found in the rules (of this particular game) to contradict it, what I said earlier stands: The correct answer is whatever the GM and players want it to be.
Well, yes, but if your first answer to any D&D rules question is Rule Zero, then there’s really not much room for discussion.
Bingo. In fact, why buy the book at all? Just go play Cops and Robbers or Orks and Looters and call it Dungeons and Dragons.
Besides, Phnord, your cite is my cite. For the GM and players to discuss and change rules, there has to be a codified set of them to begin with. Further, check that last bit : ‘when the rules are in doubt’. They’re not.
Well, at the risk of turning this into a pissing match, can you provide a cite for 2nd or 3rd edition that says specifically that?
My cite, in case you missed it, was from this page of the Pathfinder rule set:
which seems to go directly against your assertation that
is a thing that exists.
I have been unable to find anything in these rulebooks stating what would happen in the specific instance of
I’m not saying it’s not there; it may well be, I just haven’t found it.
To me, this means the rule is in doubt, and in the case that the rules are in doubt:
I own neither 2nd nor 3rd edition rulebooks for Dungeons and Dragons, and as such am unable to provide any evidence either for or against my argument, in that specific system.
Therefore, the rules are in doubt, in my mind at least. Perhaps not in yours.
If anyone has a factual cite they can provide to clarify this point, please by all means, let’s hear it… I may need it one day if it happens in one of my games!
The defect in your understanding is easily remedied. The Pathfinder ruleset you’re referring to uses ‘conjured’ to include ‘summoned’, ‘called’, and ‘created’ creatures. ‘Summoned’ creatures are the most common subset of those, due to the ubiquity of the Summon spells in the spell lists. Summoned creatures always obey (with one caveat).
Text from Summon Monster I :"This spell summons an extraplanar creature (typically an outsider, elemental, or magical beast native to another plane). It appears where you designate and acts immediately, on your turn. It attacks your opponents to the best of its ability. If you can communicate with the creature, you can direct it not to attack, to attack particular enemies, or to perform other actions. "
Note that it does not offer the creature a saving throw even if you direct it to perform a suicidal action. It does not provide any option of disobedience. You’ve summoned a manifestation of the creature, not the general article - it doesn’t care if it dies.
The single caveat to that is that the creature CANNOT use any summoning abilities it may have, and WILL NOT use any abilities that cost XP.
Text from the Summoning sub-school description : "A summoned creature cannot use any innate summoning abilities it may have, and it refuses to cast any spells that would cost it XP, or to use any spell-like abilities that would cost XP if they were spells. "
Called creatures, on the other hand, are a different ball of wax. Note that the OP DID NOT ASK about Called creatures - he asked about Summoned and Animated creatures. Calling spells are much more scarce, and are represented by Gate and the Planar Ally series, which conjure entities with whom you must bargain for their services. Not going to copy and paste the whole thing, but have a link :
So you see : Summoned creatures always obey, with that one caveat about XP abilities. Called creatures do not always obey. Since both of them are ‘Conjured’ creatures, a summary of those sentences might read : "Creatures you conjure usually, but not always, obey your commands. " It is a broad overview of conjuration as a school, not an invitation to the GM to make some secret roll to see if a summoned creature is going to spontaneously attack its summoner. Specific rules always trump general rules.
In other words, if they wanted Summoned creatures to be able to disobey, they would note that in the description of the Summoning sub-school or in the spells themselves, as they did with the Planar Ally series.
All cites from the d20 System Reference Document, which is open-source.
I wouldn’t even consider that a caveat. Summoned creatures just can’t do those things. They also can’t, say, automatically win the game for you, even if you command them to. That’s not a limitation in your control, but a limitation in their abilities.
Nevertheless, the rules say ‘won’t’, differentiated from ‘can’t’. Were I to speculate on that, I would say :
Though summoned creatures are basically a ‘copy’ of a real creature, and thus they have no qualms dying, the abilities that require tapping into one’s life-force (‘XP’) still require life-force to use, and if their manifestation were to use them, it would drain the real creature through the link they share.
But that’s just speculation.