The Skip Phase is the first part of a player's turn, before the Roll Phase. The phase is always invisible. The only effects which can activate in this phase are Skip-A-Turn, Incapacitation, and Rooster's passive. If you have either 1 or both of these statuses without Rooster activating, the skip activates, the status(es both) wear(s) off, and you get no further phases in your turn aside from the Effects Phase and a possible Forced End. If you have neither status, your turn goes on normally.
Note that this phase is not included in a turn restarted by Objection!'s Class Talent, etc. (However, this phase is included in an Extra Turn.)