Whenever there's (skill) written after the description of a skill, it means that that particular skill is an active one. Meaning there's a hotkey assigned to it in which you have to click in order to benefit from it's effects. There's a duration and cooldown timers tied to each of these skills.
Duration of each skill can be extended by creating Pearl Necklaces (+5 sec for each necklace).
Important: Certain skills have the (near) exact name (noted in parenthesizes after the semicolon) of an upgrade, but these are not related. It is assumed to be slips/bad naming from the developers.
Carl the Monolith is the only one minion that does not have any skill or upgrades.
Autotap for 5 seconds (skill #1; Sloth's Form). Sloth's form summons meteors from the sky at a rate of 10 a second for 5 seconds. Lich's son doubles that to 20. Each meteor deals the damage of a single click. Duration is extended by necklaces.
It does not matter whether the Giant Zombie is strong or not, his third skill "Dem Big Pockets" is very useful for all of Bob's minions. In every gang, there should be a Giant Zombie at level 50 minimum.
Double active skill effect for 150 seconds (skill #5; Son of the Lich)
2 minutes 30
Add 50% to The Black Lich DPS
Note: Son of the Lich skill does not change other active skills' descriptions but it has, nevertheless, an effect on the active skills. You can activate this skill before or after your other skills - the order of activation does not matter.