title_body: Do any conlangs have verbs that change form depending on the object? Are there any examples of constructed languages that have verbs with different forms depending on the object of the verb?
upvoted_answer: Yes. 
  
  I am not familiar with any “well-known” conlangs, but a quick search reveals that Klingon verbs inflect for both subject and object. This is a phenomenon called polypersonal agreement and it is very common in natural languages, and so it is only expected that it would also crop up in several conlangs. Among them, for example also my own, for which I just yesterday put up a puzzle that involves decoding the verbal system here. 
  
  I cannot currently think of any examples of a language which inflects for only the object, but it’s a rather low-hanging fruit and I cannot imagine that it has never been done before.