My level six moon druid can wild shape into a CR2 beast. I checked the monster finder and discovered there's a monster called an Enormous Tentacle.
I noticed the monster's senses include "blindsight 10ft" but I'm not sure if this replaces normal vision or is in addition to it. The monster also has "passive perception 12".
On the one hand, the monster is described as an "enormous tentacle" and I guess tentacles usually don't have eyes. On the other hand, it seems weird to give this creature a 35ft reach if it can only see ten feet.
I feel like, if a player character was fighting this thing, and they tried to argue "this monster can't see me because tentacles don't have eyes", they probably wouldn't get very far.
Is there anything in the monster manual about deciding whether a creature has vision?