Can I give it poisonous spit though? I'd love to give it poisonous spit, just I don't quite understand the natural abilities like spits and syndromes all the way.
Sure you can. Basically, you'll need to define like... three things. Or two.
One: You'll need to make custom spit. Most creatures that spit just do
[USE_MATERIAL_TEMPLATE:SPIT:SPIT_TEMPLATE]
so just add various tags to that.
There are four tags that declare how a material can inflict a syndrome.
SYN_INJECTED, SYN_CONTACT, SYN_INHALED, SYN_INGESTED
These are respectively: Through an attack that injects (your stinger tail and possibly fangs already do this), contact with the material (I'll get back to that in a sec), breathing the material as a gas (for fumes) and for eating/drunking the material (this probably won't happen.)
So basically you want to give your modded spit, defined in the creature, some contact syndrome.
Two: You want to give it an interaction or something to make it spit the spit. Let's just look at the copied one from dwarves.
[CAN_DO_INTERACTION:MATERIAL_EMISSION]
[CDI:ADV_NAME:Spit]
[CDI:USAGE_HINT:NEGATIVE_SOCIAL_RESPONSE]
[CDI:USAGE_HINT:TORMENT]
[CDI:BP_REQUIRED:BY_CATEGORY:MOUTH]
[CDI:MATERIAL:LOCAL_CREATURE_MAT:SPIT:LIQUID_GLOB]
[CDI:VERB:spit:spits:NA]
[CDI:TARGET:C:LINE_OF_SIGHT]
[CDI:TARGET_RANGE:C:15]
[CDI:MAX_TARGET_NUMBER:C:1]
[CDI:WAIT_PERIOD:30]
See the bolded part? That's where the material that is spit is defined - LOCAL_CREATURE_MAT:SPIT.
And then you'll probably also want to change the usage hint to ATTACK or something - I'm not sure on this point.
As for contact syndromes on skin and claws - eh, I'm not sure. Contact tends to require prolonged contact, like getting liquid spatters on enemies. Maybe. I bought my lab coat, you see.