Per 
Item #: SCP-XXXX
A former version of SCP-XXXXa. Picture taken by police in █████ as evidence before SCP-XXXX killed them.
Object Class: Euclid
Special Containment Procedures: SCP-XXXX must be kept in a water tight cell made of a rust proof material. No woollen clothing or items may be worn or taken into SCP-XXXX's cell except for use in testing. If wool is used in a test it must be incinerated afterwards to prevent SCP-XXXX from spreading.
Description: In its natural form SCP-XXXX looks like a dark puddle of dye that is easily absorbed by most permeable substances and will have no effect. However, if absorbed by wool, such as in clothing, the wool will become a host to SCP-XXXX. This wool host, henceforth known as SCP-XXXXa, will move itself to somewhere where it can become noticed and picked up by a potential victim. SCP-XXXXa will wait until the victim is at rest before strangling them and absorbing their blood through the capillaries under the tongue. SCP-XXXX will then leave SCP-XXXXa in search of another host, leaving the old host full of its victims blood but taking any dye from SCP-XXXXa along with it.
When outside of a host, SCP-XXXX does not move and allows itself to travel between permeable, non-woollen, substances until it finds a suitable host. Although it looks black it is actually lots of different colours of dye mixed together and it is theorised that it was once a single colour.
SCP-XXXX was found, in the form of a green and silver scarf, by police at the scene of Mr. ███ █████'s murder. He had been strangled to death and the police from the █████ police station believed SCP-XXXXa had been used as the murder weapon. It was taken to the police archives as evidence but killed ██ police officers before the SCP Foundation located and captured it.
SCP-XXXX remained dormant in a test tube for ██ years until 20██ when it was knocked over during a test and was absorbed into the lab coat of Dr. █████. SCP-XXXX killed a further ███ researchers and security officers before being recaptured █ days later. SCP-XXXXa was transferred to its current, waterproof, cell in the form of a blue woollen hat that previously belonged to Jr. Researcher ██████ before her death.
Addendum: Dr. Masino Test Log
Test 1 - ██/02/19
Subject: SCP-XXXXa, D-33124
Procedure: D-33124 put SCP-XXXXa on their head.
Results: SCP-XXXXa climbed off of D-33124's head and began to strangle them. After D-33124 lost consciousness SCP-XXXXa crawled into their mouth and began to drain their blood. After about five (5) minutes SCP-XXXXa crawled out of the mouth of D-33124 and sat on the floor of the testing area whilst SCP-XXXX drained out of it, leaving SCP-XXXXa blood red. Although SCP-XXXX came into contact with its former host afterwards it was not reabsorbed by it. Analysis of the body of D-33124 showed only minimal traces of blood remaining.
Analysis: SCP-XXXX drains its victims of blood almost completely in approximately five (5) minutes and will not return to an old host.
Note: That was disgusting. I wonder if the size of SCP-XXXXa changes how much blood it can hold. - Dr. Masino
Test 2 - ██/02/19
Subject: SCP-XXXX, one (1) short piece of wool 50cm in length, D-71198
Procedure: The piece of string was introduced to SCP-XXXX and then D-71198 was sent into the testing chamber.
Results: SCP-XXXX adopted the string as its host, then strangled D-71198 and drained their blood in around five (5) minutes before leaving SCP-XXXXa. Analysis of the body of D-71198 revealed almost no traces of blood.
Analysis: SCP-XXXX can absorb all the blood from its victim in around five (5) minutes regardless of size of SCP-XXXXa.
