Observation
apashtau s/he uses it nitapashtan I use it
katau s/he hides it nikatan I hide it

Some verbs take VAI (animate intransitive verb) endings even though they are transitive, i.e. take an object (it). These verbs are called VAI+O (O = ‘object’); in Algonquian linguistics, they are also sometimes referred to as VTI2 or VAIT.

These verb stems end with a long a – or, more precisely, with the morpheme -ta (like apashta- and kata- above) – and they conjugate almost like VAIs with long a stems.

VAI+O (with long a stems) VAI (with long a stems)
nitapashtan I use it nipapatan I arrive by vehicle
tshitapashtan you use it tshipapatan you arrive by vehicle
apashtau s/he uses it papatau s/he arrives by vehicle

Not all verbs ending in -tau are VAI+Os, though. For example, verbs ending in -patau running, driving do not take an object.

Where VAI+Os differ from VAIs is in the way that they form their passives. While VAIs form their passives (also called indefinites) with -nanu, VAI+Os form them with -akan like VTIs.

Passive or Indefinite Forms of VAI+Os Passive or Indefinite Forms of VAIs
apashtakanu it is used papatananu people arrive by vehicle
katakanu it is hidden aiamiananu people pray, there is a mass