Grosstropod, the snot snail!
It probably has Gooey or Liquid Ooze as an ability.

Grosstropod is often found around the homes of those sick with colds or the flu. It’s considered a pest but may be connected to quicker recovery from sickness. It’s ‘shell’ is fragile and made of used tissues it likes to collect from the sick people it shadows. It like Cubchoo.