Will this snail eat my mystery snail?

[ravi_tetra]

I have one mystery snail and another pest snail that grew on its own (I have live plants) . My question- the pest snail is now on the shell of my mystery snail. Is this a problem? Are they just being friendly or is my pest snail feeding on the bigger mystery snail?

 

[ADsnail]

It's a piggyback ride, not cannibalism Pest snails can reproduce rapidly, so that's going to be the problem.