Slinky - 165 R6
Stats
Armor - 68240
Reality - 150662
Normal Crit - 189
Slinky does only fantastic damage so normal crit doesn't make sense here & the role of the slinky is to keep the team alive by spamming shields.
His skills & Powerline disc provide a good amount of reality to himself & to allies when shielded. So, his reality will always be enough for him.
Therefore, First Mod should be an HP mod with Armor Upgrade to save from normal damage, I know dog already have a good amount of armor but the more the better for the team.
The Second Mod should be again HP mod with Shield Upgrade, so that dog can get instantly more armor & reality from purple skill. This can also be spammed by Baymax red skill as well or some other toon as well - I will update later on this.
Now, slinky will be great for a stall team in arena & War, so just give him as much as reality & armor from purple skill, so for a good stall team Third & Fourth Mod should be Skill power mod with Purple Skill Upgrade
Mod Matrix
Another Suggestion
Thanks for reading