A new phase of toddlerhood

Lately I've been witnessing a few signs that Sam may be entering (or is completely in) a new phase of toddlerhood.

• Most requests and commands are met with ignorance (he just ignores us), resistance (if we make him do something, he squirms, screams, runs away), retaliation (he hits, throws, swings, etc.) or outright disobedience. 
• For example, after bath tonight, I knelt down and told Sam that Matthew was in bed and we needed to be quiet in the hallway. He then ran down the hall (naked, of course) squealing and shouting.
• Another example. Sam tried to run over Matthew with the digger (his little bulldozer-like riding toy). The digger is in timeout. 
• Yet another example: Sam smelled dirty this morning, so I asked him if he had a dirty diaper. He said "No, I'm fine." I told him that, no, I thought he needed a diaper change. So then he ran in circles around the kitchen and living room area. I finally caught him and he became the plank, then went boneless and otherwise squirmed, screamed and whined.
• Again, another example. Tonight before bath I thought I would have Sam sit on the toilet first before getting into the tub so we could avert another incident like I wrote about previously. He sat on the toiler for a minute or so, then he got into the tub and peed.