do, say or believe anything, however unlikely or inadequate which seems to offer hope in a desperate situation.
This expression comes from the proverb a drowning man will dutch at a straw which is recorded in various forms since the mid 16th century.
catch a cold = catch cold
become infected with a cold.
encounter trouble or difficulties, especially financial ones. – informal
2001 - Financial Times - Most observers expect house prices to rise... depending on whether the UK economy continues to grow smoothly or whether it catches a cold from the US.
catch your death = catch your death of cold
catch a severe cold or chill - informal
catch a Tartar
encounter or get hold of a person who can neither be controlled nor got rid of
meet with a person who is unexpectedly more than your match.
The Tartars (or Tatars), a combined force of central Asian people including Mongols and Turks, established a vast empire during the Middle Ages under the leadership of the j warlord Genghis Khan and were a byword for ferocity.