Clicker (sample creature, need notes)

[beckmen]

I generally make my own creatures, albeit based on existing TV/movie creatures or artwork I see. I have had players come up against these creatures, but am still refining the process of making them, so I am looking for advice.

This is a creature I made for 5e. Looking for general notes, especially as to the Challenge Rating. They are designed to go against 6th level characters.

PS: Is there a dedicated thread around here to post homebrew monsters and have others estimate what their CR should be? That is one aspect of making them that I know I am not very good at, and it's hard to figure out encounter difficulty when I can't properly estimate a creature's Challenge Rating.

PPS: Feel free to use this, alter it, whatever if you like it.

Clicker
The clicking and hissing of their communication portends the arrival of these 7-foot tall bipedal insectoids with massive, Mantis-like raptorial forelegs.

• Medium Aberration, Chaotic Evil
• AC: 16 (natural armor)
• HP: 45 (5d10+20)
• Speed: 35 feet
• Senses: Darkvision 120 feet, Tremorsense 60 feet
• Passive Perception: 15
• Languages: Clicker language
• Challenge Rating: 4 (1,100 XP)

STR:20 (+5) DEX:12 (+1) CON:18 (+4) INT:12 (+1) WIS:16 (+3) CHA: 8 (-1)


Antennae: The Clicker has Advantage on Wisdom checks that rely on smell, hearing, or tremorsense


Toxic Blood: Whenever the creature is below its maximum hit point value, any other creatures (besides other Clickers) within 10 feet of it must make a DC-20 Saving Throw or take 2d6 Poison damage or half as much damage on a save. This effect continues until ten minutes after the creature has been killed, in which case the poison dissipates.


ACTIONS:


Multiattack: The Clicker makes two Slash attacks.


Slash: +7 to hit, 2d6+5 piercing damage