So in your experience, what are the monsters that are laughably weak for their CR? What are the monsters that are a surprising threat at their CR, and maybe underestimated?
For Over-CR, having used one recently....is the Mummy Lord hands down (CR 15). It is geared as a somewhat melee oriented legendary monster, but its AC and hitpoints are ridiculously low for its CR. Even if you max its hitpoints per hit dice, it is still too weak imo. The mummy lord can be taken down by a single party member let alone the group. Its offense is geared towards a fear effect that most parties of that level has immunity to, disease that takes too long to be a concern, and a one use harm spell that is still not that impressive to 15th level characters.
I think this monster would be weak even as a regular monster....it is not even close to a legendary of that CR 15.
For under-CR, my vote goes to the Githzerai Zerph (CR 6). The very definition of CR is that you need a party of this level or higher to deal with its abilities. Parties beneath that CR may really struggle against its effects.
The Githzerai stats are pretty tame for the most part, until you see.....Plane Shift 1/day. Plane Shift is a monster spell for even a high level party to deal with. A 6th level party has no chance if this effect goes off. This one monster can completely derail a campaign, as suddenly the party goes from whatever adventure they are on to having to conscript planar travel help and goes off to find their lost friend (assuming they even know where to look). It is far easier for a party to deal with a character death (revivify...3rd level spell) than it is a plane shift.
Really the Githzerai just needs a change to say "Plane Shift 1/day (SELF ONLY)" and it would then be just fine.
What monsters have you seen where the CR just doesn't cut the mustard?
For Over-CR, having used one recently....is the Mummy Lord hands down (CR 15). It is geared as a somewhat melee oriented legendary monster, but its AC and hitpoints are ridiculously low for its CR. Even if you max its hitpoints per hit dice, it is still too weak imo. The mummy lord can be taken down by a single party member let alone the group. Its offense is geared towards a fear effect that most parties of that level has immunity to, disease that takes too long to be a concern, and a one use harm spell that is still not that impressive to 15th level characters.
I think this monster would be weak even as a regular monster....it is not even close to a legendary of that CR 15.
For under-CR, my vote goes to the Githzerai Zerph (CR 6). The very definition of CR is that you need a party of this level or higher to deal with its abilities. Parties beneath that CR may really struggle against its effects.
The Githzerai stats are pretty tame for the most part, until you see.....Plane Shift 1/day. Plane Shift is a monster spell for even a high level party to deal with. A 6th level party has no chance if this effect goes off. This one monster can completely derail a campaign, as suddenly the party goes from whatever adventure they are on to having to conscript planar travel help and goes off to find their lost friend (assuming they even know where to look). It is far easier for a party to deal with a character death (revivify...3rd level spell) than it is a plane shift.
Really the Githzerai just needs a change to say "Plane Shift 1/day (SELF ONLY)" and it would then be just fine.
What monsters have you seen where the CR just doesn't cut the mustard?