Cryx common mistakes

Ghostly - it does not allow you to move through models

Bloat Thrall - it's gun does not cause the continuous corrosion effect, it only is corrosion type damage

Seether - an autonomous Seether (created via the Combine's Dark Industries for example) does not get the free FOC because autonomous jacks cannot be allocated FOC and Soul Drive use the wording "this model is allocated 1 additional focus..."

Seether - You can only allocate up to 2 additional FOC to the Seether, not 3 because Soul Drive is done via allocation. So no 4 FOC Seether.

Seether - Disruption prevents it from receiving the FOC from Soul Drive because it is allocated

Deathjack - Disruption does not prevent it from getting up to 2 additional FOC from skulls of hate because it is not allocated. Likewise, any souls it has are not lost when it is Disrupted, and they still turn into FOC on your next turn

Deathjack - cannot be allocated any FOC if it has 3 or more souls which turned into FOC. i.e. Deathjack starts the turn with 0 souls. You can allocate it up to 3 FOC, and then it gets an additional FOC for each skull of hate. If Deathjack started the turn with 1 soul, that soul gets converted to 1 FOC, you can allocate up to 2 more FOC, then you get an additional FOC for each skull of hate etc...
basically souls turn into FOC first, then when it comes to allocation, you get to allocate FOC, but you cannot exceed 3 FOC as a result of allocation, , then the Skulls of Hate rule kicks after FOC allocation and give up to 2 additional FOC.

Necrosurgeon - it can have an unlimited number of corpse tokens, but can only create 3 meachanithralls per turn. You cannot create a new unit this way and must have at least 1 mechanithrall or Brute thrall model of an existing unit in play.

Epic Goreshade feat - cannot be used to create new units.

eSkarre feat - Trample gets around eSkarre's feat.

Pistol Wraith - You cannot shake the effect of Death Chill.

Soulhunters - only incorporeal when activating in Darragh Wrathe's command area.

Skarlock - not effected by Lamentation.

eSkarre's Blackspot - Only one attack generated after thresher, trampling or killing spree (Gerlak)

Machine Wraith - cannot charge to meld into a jack

Cull Soul - If 2 models are eligible for a soul token, only one gets it. The one nearer to the living enemy model that died gets it unless specified otherwise.