Alien Marī

Alien Marī is a Japanese anime series created by Waku Yaniko.

Plot
Marī is a human-like alien from planet Orto who, after using a training spaceship, crashed onto Earth where she start flying around to get a look around but while she was flying, she was hit by a baseball thrown by Makoto Varaboke. She then challenged him into a game of tag where if she wins, she'll conquer Earth but if Makoto wins, she'll live with him as his future wife but while she was having fun getting away from Makoto, he won by sneakingly grabbing her by her chest and, due to their deal and the fact that the spaceship was destroyed by crashing, she is now living with Makoto as his future wife whether she likes it or not.