Backstory:

He is quite silly, but he can be serious when necessary, capable of manipulating water and light, despite his silly appearance, he is quite capable of defending himself, he usually trusts everyone and considers them friends, however, he can know when someone is no longer trustworthy.

During a genocide route, Madsune attacks him in puzzles, however, he survives the first attack plus two other ones before going down, no Undyne to save him.

Encounter Text:

[Neutral/pacifist]

OM: Hey friends!
OM: What are you doing here in Skill Town?
OM: Heh, it almost sounded like I said you two lack skill.
OM: But it wasn't my intention, got it?

[Genocide]

{SLASH!}

OM: Ouch...
OM: That was uncalled for.
OM: But I guess you two want a battle, huh?
OM: Fine, I guess I can still fight after that...

Check Text:

*Oceanmon the fish monster.
*The ocean is rising, but this fish is going down.