nod that's probably the most sensible response.
To help others understand the potential risks, the creation of a 'tulpa' appears to involve hacking the way your sense-of-self (what current neuroscience identifies as a function of the right inferior parietal cortex) interacts with your ability to empathize and emulate other people (the so-called mirror neuron / "put yourself in others' shoes" modules). Failure modes involve symptoms that mimic dissociative identity disorder, social anxiety disorder, and schizophrenia.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.