For me, monsters are all about vibes.
Minotaurs? Big burly dudes hung like horses (often literally with horse cocks, rather than a bull's), there to overpower, dominate, and physically stretch their partners with their girth. A lot of that is just human adjacent power fantasy. Masochists and size queens exist in real life, a minotaur just has the potential to crank some of that up to 11. Tentacle monsters are often used as bondage adjacent. They feed into a lot of the same domination and submission roleplay as your more traditional BDSM, but again cranked up to 11 with the injection of the supernatural.
Where the vibes start to get fucked for me is when things get too far away from being human adjacent, or in some way an extension of more typical human kinks that I already enjoy. For example, I think breeding and potentially or actually getting someone pregnant is super hot, especially as part of power play. But actual pregnancy or birth? Nope, not interested. So monsters that play into pregnancy or birth kinks but crank them up to 11, stuff like insect aliens with ovipositors that lay eggs that are later 'birthed' as eggs or live young? That stuff triggers the vibe check. That content is not for me.
