limpit mine
Somebody who is very clingy throughout your relationship, never leaving your side (like a limpit) and then (without warning) suddenly goes off!
Person 1: That Heather Mills was like a limpit mine on Paul Mcartney. One minute he couldn't get rid of her, the next she just went off!
Person 2: Those limpit mines can cause a lot of damage when they go off.
Person 2: Those limpit mines can cause a lot of damage when they go off.