In principle, and as a matter of grammar, this is easy: cogito ergo --- sum, where --- is an adjective meaning "dangerous". The only thing to do is choose the adjective.
But this is harder than you might think, because whereas "dangerous" in English is a word which has acquired some postive connotations, the Latin adjectives seem to lack that -- indeed, they generally have rather negative ones.
periculosus or periculosa if you are a woman. But this is normally applied to places or situations, not (so far as I can see) to people. It doesn't feel like good Latin to me.
lubricus literally "slippery" can be applied to people whose arguments are dangerous: but it has overtones of craftiness, trickery or deception which you do not want.
infestus looks like the closest match: hostile, antagonistic, dangerous. But it really needs to be qualified by an explanation of what you are dangerous too or it might simply be taken to mean savage, violent, obnoxious.
What sort of danger do you see your thinking-self as posing? To whom?