He is often very suspicious. He might immediately think it's some kind of trick by the Marauders or their descendants. He'll likely try to figure out how to use it to his advantage against those he dislikes.
Snape could be both intrigued and frustrated. Intrigued because it's a magical object he's never seen before, but frustrated because it doesn't easily give up its secrets. He might spend hours trying to unlock its full potential, all while muttering darkly about the Marauders. For instance, he may try different spells on it, and when they don't work, his temper might flare. He might also be a bit worried that it could be used against him if it falls into the wrong hands, like those of James Potter's son, Harry.
Another plot could involve Snape finding the map and realizing that it holds secrets about Hogwarts that could be used against Dumbledore. However, as he delves deeper, he discovers that the Marauders had a deeper connection to the school's secrets than he thought. This could make him question his own understanding of the school and its history, and also his relationship with the Marauders.
He would probably be in shock. Snape has spent so much time around Harry in one way or another throughout his years at Hogwarts. His immediate reaction could be disbelief. He might stand there frozen for a moment, unable to process what he's seeing. Then, the full weight of the situation would hit him, and he could break down in a rare display of raw emotion.
He could be secretly worried. Snape might use his knowledge of potions and dark magic to try and find a cure or at least a way to stop the bleeding. He may also be conflicted, as his past relationship with Harry and his loyalty to different sides in the wizarding world play a role in how much he wants to help Harry.
Snape's reaction could be quite mixed. On one hand, he might be angry at Dumbledore for not doing more if he knew about the abuse. He may also feel a strange sort of empathy towards Harry. After all, Snape himself had a difficult childhood. So, he could start to be a bit more lenient with Harry in his classes and try to subtly offer support.
Well, Snape has always had a complex relationship with Harry. When he finds Harry cutting himself in this fanfiction, he might be angry at first, thinking it's a sign of weakness. But then, as he realizes the depth of Harry's pain, he could soften. He might start to see Harry more as a troubled child rather than just James Potter's son. Snape could use his knowledge of potions to create something to heal the physical wounds and also try to offer some form of emotional support, albeit in his own gruff way.
Snape's reaction could be multi - faceted. He might be angry at those who are abusing Draco, but also a bit conflicted because of Draco's family's ties to the Dark side. He could use his position as a teacher to give Draco some extra guidance and support, perhaps in the form of private tutoring sessions where he can also check on Draco's well - being more closely. He may also start to question his own views on the Malfoy family in general.
Snape might be suspicious at first. He might think it's some sort of trick or part of a bigger plot. However, as he observes Hermione more closely and realizes the genuineness of her situation, his attitude could gradually change to one of reluctant assistance. He might even offer some words of wisdom, albeit in his typical sarcastic way, to help Hermione regain her strength.
In the fanfic, Snape's reaction could be multi - faceted. He might start by investigating the abuse more deeply. He could use his skills as a Potions master and a former Death Eater to find out who is behind the abuse. And then, he might take steps to ensure Harry's safety. This could involve enlisting the help of other teachers or even trying to get Dumbledore more involved. He may also start to teach Harry some extra skills or give him potions to help him deal with the emotional and physical trauma of the abuse.
Snape might initially be shocked. He's not one to show much emotion openly, but internally he could be very disturbed. He might start investigating what happened to Hermione immediately, using his skills in potions and magic to try and find a cure or at least understand the cause.
Snape could initially be skeptical. Given their long - standing enmity, he might not believe that Harry's apology is sincere at first. He might respond with a cold glare or a sarcastic comment, like 'Potter, your apologies are as empty as your head.'