They did. It was in an unreleased 3rd season episode called Amok Time 2; the teletubbies beamed aboard the ship and annoyed Spock so much that he blew a fuse, killed them, and stuffed their bodies into the warp core. The rest of the crew was very sympathetic. Later in the episode, Barney came aboard looking for the 'tubbies and Kirk kicked him in the junk. Again, the rest of the crew was very sympathetic. 
