If you have recently received a very small amount of BTC in your wallet unexpectedly, you may be the target of a "dusting attack" designed to deanonymise you by linking your inputs together - Samourai users can mark this utxo as "Do Not Spend" to nip the attack in the bud.

https://twitter.com/SamouraiWallet/status/1055345822076936192?s=09 via /r/Bitcoin http://bit.ly/2qc74NA