Yes it is a pseudoplastic, as stress is applied to it, it becomes more viscous, causing the person walking on it to sink. The more they struggle, the more stress is applied to it, the faster they...
No
...at least at STP (Standard Temperature and Pressure)
'Non-Newtonian' behaviour occurs only under very special circumstances, i.e. the subatomic level or at environmental extremes, e.g. near...