What do you call someone who is easily influenced?

I am looking for a term with bad connotation. I am aware of the popular terms like "he/she has no personality", pliable, malleable, weak-minded but i couldn't find any more on the insulting side. It could be an idiom or a single word.

For example:

• I just bought this bag yesterday and he came today with a new one too

• He never talks to her and now he does –just because I did in the morning. He is such a ____

Solution 1:

These seem to fit your criteria:

impressionable - easily influenced because of a lack of critical ability.

susceptible - likely or liable to be influenced or harmed by a particular thing.

Note these words fit your title and description much better than they do your examples.

Solution 2:

Consider credulous. While this is not necessarily a term with a bad connotation, it can be considered a negative attribute. Here's another post asking for a similar word: Word for people easily influenced by propaganda

Solution 3:

Try a thesaurus search on Gullible or Follower

Some words you might like are Patsy, Sucker, Lemming, Sheeple, Lackey, Flunkey, Copycat, Follower, Aper, etc.